--- product_id: 305202509 title: "Donegan DA-10 OptiVisor Headband Magnifier, 3.5x Magnification, 4\" Focal Length" brand: "donegan optical" price: "7085431₫" currency: VND in_stock: true category: "Donegan Optical" url: https://www.desertcart.vn/products/305202509-donegan-da-10-optivisor-headband-magnifier-3-5x-magnification-4 store_origin: VN region: Vietnam --- # 4-inch precise focal length 3.5x crystal-clear magnification Genuine leather padded comfort Donegan DA-10 OptiVisor Headband Magnifier, 3.5x Magnification, 4" Focal Length **Brand:** donegan optical **Price:** 7085431₫ **Availability:** ✅ In Stock ## Summary > 🔎 Elevate your detail game—see what others miss! ## Quick Answers - **What is this?** Donegan DA-10 OptiVisor Headband Magnifier, 3.5x Magnification, 4" Focal Length by donegan optical - **How much does it cost?** 7085431₫ with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.vn](https://www.desertcart.vn/products/305202509-donegan-da-10-optivisor-headband-magnifier-3-5x-magnification-4) ## Best For - donegan optical enthusiasts ## Why This Product - Trusted donegan optical brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Custom Fit Comfort:** Adjustable headband with orthopedic leather padding molds perfectly to your head. - • **Seamless Usability:** Visor easily flips up when not in use—stay focused without interruption. - • **Hands-Free Precision:** Snap-in binocular lenses deliver sharp, strain-free viewing for hours. - • **Durable Craftsmanship:** Lightweight yet robust design made in the USA for professional-grade reliability. - • **Versatile Magnification:** 3.5x glass prismatic lenses optimize clarity for jewelry, crafts, and detailed work. ## Overview The Donegan DA-10 OptiVisor is a premium hands-free headband magnifier featuring 3.5x ground glass prismatic lenses with a 4-inch focal length. Designed for professionals and hobbyists alike, it offers adjustable, padded leather comfort and a flip-up visor for seamless use. Ideal for precision tasks like jewelry-making, watch repair, and fine crafts, this durable USA-made magnifier reduces eye strain while delivering crystal-clear focus. ## Description The Donegan OptiVISOR is a hands-free, headband binocular magnifier that has optical glass lenses that are ground and polished into prismatic lenses for quality and clarity, and is available in multiple dioptric strengths (indicated by the number in the model) which provide specific magnification power (X) at specific focal lengths, or distance from object. This magnifier enhances the size and resolution of an object or image, and is commonly used for a variety of applications such as jewelry-making, watch- making, needlework, artwork, electronic inspection, book-reading, print inspection, and stamp-collecting.The OptiVISOR magnifier features replaceable binocular lenses that have beveled edges that are mounted in an interchangeable plastic frame. An adjustable headband with padded leather comfort band conforms to a variety of head sizes and provides comfort for hours of continuous use. It can be worn over prescription or safety eyeglasses. A durable, plastic visor tips up above the forehead when not in use. Spring-loaded pivot screws hold the headband in a raised or a forward-facing position. The magnifier weighs 0.67 lbs. It has a one-year limited warranty.Diopter (D) is a technical term for the measurement of the light curvature and thickness of a lens. A dioptric number and a magnification number are not the same thing. Diopter strength represents a specific magnification power (X). For example, a 5-diopter provides 2.5X magnification (at a distance of 8”). See the magnification chart. The higher the diopter, the more magnification a lens can provide. As magnification increases, distance to the object (focal length), and field of view (diameter, or narrowness of view) decreases. Magnifiers and prescription eyeglasses have a diopter value, such as 1.5 or 2. The dioptric strength of an accessory lens, such as prescription eyeglasses or an eye loupe, must be added to the dioptric strength of the magnifier to calculate total magnification.Magnifiers are devices used to enlarge the visual appearance of an object or image. Magnifiers come in a variety of styles such as hand-held, headband, standing, clip-on, eye loupe, and those that hang in a necklace form, or fit in a trouser pocket. Magnifiers are commonly made of plastic or glass. They can have one or more lenses with varying magnification abilities, and can have a binocular configuration with a single lens, or two separate lenses. They are sometimes used with LED or fluorescent light sources to help control viewing capabilities. Magnifier ability is often expressed as magnification at a specific length. For example, 1.75X at 14” means that when a magnifier is held at 14” from a viewer’s eyes, the object will be magnified 1.75 times (X) its actual size. As magnification increases, viewing areas and focal length decrease. Magnifiers sometimes have a diopter number, expressed as + or -D, which is a measurement of strength (or power) of the lens. Some magnifiers are marked with a dioptric number on the lens. A high diopter number has a higher magnification than a low diopter number. Aspheric magnifiers, unlike spheric magnifiers, produce a sharp image to the edge of the lens for less distortion. Magnifiers are widely used in jewelry inspection and fabrication, watch-making, needlework, artwork, reading, print inspection, and stamp-collecting.Determining MagnificationDiopter Magnification Focal length (Distance from object) Sample view 20/20 vision 20" (50.8cm) 2-diopter lens 1.50X 20" (50.8cm) 3-diopter lens 1.75X 14" (35.56cm) 4-diopter lens 2.00X 10" (25.4cm) 5-diopter lens 2.50X 8" (20.32cm) 7-diopter lens 2.75X 6" (15.24cm) 10-diopter lens 3.50X 4" (10.16cm) Donegan Optical manufactures and distributes precision visual devices for hobbyists and professionals in industry, home, office and crafts applications. The company was founded in 1952 and is headquartered in Lenexa, Kansas.What’s in the Box?OptiVISORInstruction manual ## Features - Headband binocular visor with snap-in 3.5X magnifying lens plate for hands-free viewing - Ground and polished glass prismatic lens for improved focus and reduced eye strain - Visor size-adjustment knobs for customized fit - Visor tilts out of way when not needed - 4" focal length for a variety of uses. Genuine leather comfort band: Padded orthopedic felt adds to comfort ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0015IP380 | | Batteries Required? | No | | Best Sellers Rank | #124,752 in Office Products ( See Top 100 in Office Products ) #1,300 in Reading Magnifiers | | Brand | Donegan Optical | | Colour | Black | | Country of Origin | USA | | Department | mens | | Global Trade Identification Number | 00633096000465 | | Handle Material | Leather | | Item Weight | 227 g | | Item model number | DA-10 | | Lens Material | Glass | | Magnification Strength | 3.5 x | | Manufacturer | Donegan Optical | | Net Quantity | 1.0 Count | | Product Dimensions | 25.9L x 20.3W Centimeters | | UPC | 789164035492 633096000465 654207152040 | ## Product Details - **Batteries Required?:** No - **Brand:** Donegan Optical - **Colour:** Black - **Item Weight:** 0.5 Pounds - **Lens Material:** Glass ## Images ![Donegan DA-10 OptiVisor Headband Magnifier, 3.5x Magnification, 4" Focal Length - Image 1](https://m.media-amazon.com/images/I/41yy8++1i7L.jpg) ![Donegan DA-10 OptiVisor Headband Magnifier, 3.5x Magnification, 4" Focal Length - Image 2](https://m.media-amazon.com/images/I/71Is0pkflnL.jpg) ## Questions & Answers **Q: How is this product better than magnifying glasses?** A: I advise you to read the perfect comment that chezphyl answered on June 1, 2014.I copy it here for you: It's easy to "bump" them up when not in use and back down when you need them. They remain on your head so you don't have to lay them down somewhere. When positioned down quite far you can look up (over the top of the eye glass frame) to see things normally, such as TV or another person. I use them this way a lot of the time. There's also an optional light that attaches to the unit if you need more light on the work object. I have not purchased that, because I have numerous work lights that suffice. Pay close attention to the distance you will have from your face to the work piece as this will determine the lens power to order. One set of lenses is included, but you can purchase additional lenses if you plan to use the headset for hobbies requiring varying distances. If you presently wear regular prescription glasses you can wear them under the device. Previously, I tried attaching magnifying glasses onto my reading glasses and they didn't attach well, but that may have been because my glasses were too small or the quality of the magnifying clip-ons I chose. This is the most convenient solution I've found so far for very small, very precise stitchery. **Q: light** A: If you are asking if it has a built-in light the answer is no. If you are asking if it is light in weight, the answer is it is not heavy enough to be uncomfortable. I have not weighed it but it fits well on my head and indeed when I am engaged in a project, I sometimes forget it is there. It provides a clear, undistorted view of whatever you are working on. The focal length is about right for working on small objects. I do not know if the less expensive magnifiers have lenses comparable to the one in the Donegan Optivisor. **Q: I am very nearsighted and must wear glasses all the time. I am assuming this tool is only to be without glasses . is that correct?** A: Actually i wear it with my glasses all the time without any trouble. **Q: Is this made in China?** A: No. It's made in the USA. I avoid buying anything made in China. ## Frequently Bought Together - Donegan DA-10 OptiVisor Headband Magnifier, 3.5x Magnification, 4" Focal Length - Donegan LP1 OptiLOUPE Magnifier for OptiVISOR, Adds 2.5X Magnification - Quasar Led Lighting System for Optivisors --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.vn/products/305202509-donegan-da-10-optivisor-headband-magnifier-3-5x-magnification-4](https://www.desertcart.vn/products/305202509-donegan-da-10-optivisor-headband-magnifier-3-5x-magnification-4) --- *Product available on Desertcart Vietnam* *Store origin: VN* *Last updated: 2026-05-21*