LSE Lighting (2-Pack) 602805 UV Replacement Lamps Compatible with Viqua Max C, D, D4 Systems – Trojan Sterilight Equivalent – High Performance UV-C Bulbs – Designed in USA

The BAD: We only received 1 when we should have received 2 but a replacement is being sent.The (very) GOOD: Contacting the manufacturer (Viqua) about our D4+ system which came with the (new) home we purchased, they insisted that ONLY their bulbs would work so we purchased one for nearly $200! Long story short we didn't want to pay that much in the future for a bulb that needed to be replaced every 10-12 months so we researched the heck out of compatible bulbs and manufacturers. Upon reading about LSE we decided that was the company to go with because that's what the company does. They manufacturer UV bulbs for industry. In fact I believe they actually manufacturer for Viqua! We got a TWO PACK for $65+tx. One single OEM Viqua bulb costs $150 at the minimum. So, for the price of one Viqua bulb we can get four LSE ones!How do they fit and work? The bulb(s) we received were individually wrapped and placed in a cardboard tube (1 per tube) and then in a padded box. They (it) arrived within a couple of days in perfect condition. The only minor issue, which has been pointed out in other reviews, is that you need to break off the two shortest tabs in order for the harness to fit which is no big deal to do. Just get pliers, grip at the bottom part of the tab and gently pull towards you. It snapped right off with zero damage. Once those were removed it fit perfectly and all the lights were green! It's the same exact everything (except those tabs) as the OEM bulb.I'm not sure why others give less than great reviews, maybe because they ordered the wrong bulb or didn't know enough to pull the tabs off. Now, Granted you shouldn't have to snap off tabs but that's worth the nearly $150 savings for something that works just like the OEM! As long as it says it fits your unit it will work.

Just Replaced light, if I had done it in the return window I think I may have actually returned them. Too much time wasted on figuring out what the problem was and then customizing the plug portion, which should have took all of five minutes if that. Just don’t feel they were worth the money saved, not to mention let’s see if they last their one year. In fact on first install, light was blinking green finally turned to red. Pulled out and reset, hoping when I go back down to the basement it’s still green.The problem is the pins are very inaccurately set into place I used the old bulb (Vique) to take measurements and reset very carefully with needle nose pliers. Apparently the two pins should be 1/4 inch center to center I had to bend them in a hair and I used a spark plug gap gauge to reset the pins inwards towards the center plastic Finn. And as close as I can tell because the pins are set into the plastic mold out of position the plug is not 100% properly seating, but seating enough to work, hopefully. Oh and I also had to snap off the two outer fins adjacent/parallel to the pin sides. they seem to be molded slightly smaller in words than the original. So as close as I can tell to make a very long story short the plastic plug housing and pin set up is totally out of whack as to measurements.

These lamps worked fine. I ordered 4 of them on two different occasions. All 8 lamps worked no problem. LSE Lighting has another offer for these same lamps here on Amazon (single lamps- not a 2-pack like these). The plastic on those lamp heads was very poor quality and most of the lamps didn't work. These are made with better quality plastic and all lamps have worked. Be sure to order these and not the others!

It'll works but you have to break some plastic tabs off the side to get it to fit the D4.

Second time purchasing these lamps. The work and last the full year. Easy install the first time this order the taps would not allow the connector to seat a fraction to larger. I had shave some plastic off the tabs. Easy fix.

I‘ve purchased the single and the two lamps over three years. Both fit perfectly and lasted over a year; I replace every 365 days. I just ordered 2 more lamps on 9/10/21.

These bulbs are purported to work as the OEM Viqua bulbs but the system says not working resulting in a constant beeping to tell you there is a problem.

I've now ordered this 2-bulb product twice for my Trojan C4 system.For my first purchase, the good news is that both bulbs fit my C4 system just fine. But, the first bulb failed after 6 months, and the second bulb failed just before the 4th month. The bulbs should be changed annually, so they failed far too quickly, and I needed three bulbs for the one-year period during which I should've needed only one bulb.Despite that these bulbs failed too quickly, *conceptually,* they're still a better value than buying just one genuine bulb for one year. So, I reordered these bulbs. I received the new bulbs today, and this time, NEITHER bulb fit my C4 system. To me, it looked like the little "prongs" atop both bulbs were bent inward a little so they wouldn't fit into the slots in the plug, and the little "tabs" atop both bulbs weren't wide enough to enable the plug to fit onto the cap of the bulb. The variances were very slight from the previous bulbs that had fit, but the variances were enough to affect the fit of the bulb.In light of that most recent development, at least for now, I'm giving up on these bulbs. I found a business that sells the genuine C4 bulb for $108 with free shipping, and at that price, assuming that it will last for a full year as my other genuine bulbs always have, it's a better value for me than buying three bulbs and monkeying around with bulbs that don't fit.