Global Art Materials 120-Piece Leather Pencil Case, Black

Q: height and width of case?

It depends on which size...found dimensions on Blick: https://www.dickblick.com/products/global-art-classic-leather-pencil-cases/#itemspecs

Q: Does this hold 120 prismacolor premier pencils? Or will it only fit 80 like previous reviews have stated

I agree it only holds about 80 with a tight squeeze. 120 can be done but it is Very difficult to get them in and out I would be afraid to break my pencils forcing them in. I only use it for 80. I have Prismacolor pencils. Maybe if the elastic stretches out it will be easier. It is a very nice case.

Q: Would Copic Sketch markers fit in these cases?

Yes, the Copic Sketch markers will fit into the loops. One loop holds one marker meaning the 120 count pencil case will hold 40 markers.

Q: can this hold gel pens?

It would depend on the width of the pens. It will hold Staedtler Fine Point markers 3 to a slot if you alternate ends (two in one direction and one opposite). It is a tight fit and would get easier once the elastic "relaxes". It holds three Polychromos (snug fit) and easily handles Prismacolor Premiers. Staedtler pencils are very easy to fit in. If you have any of these brands you can use them to judge how many gel pens you can insert. I would guess you could easily fit 2 per slot and that would give you 80 gel pens. It all depends on the width of your brand of pens.