what is the dimension of the inside of the case, the width inside? I have an item that measures 3/4 of an inch wide, will it fit in case?
Yes. It's approx. 1 1/4" or 33 mm.
Since I have several of these, it was easy for me to take a few rough measurements for you. The inside compartment of the case is 1/2" wide, 2 1/4" long, and 3 1/2" deep. Unfortunately, with this case, your item will not fit. Witz does make larger cases that may work better for you.
Nope. Two C cards and two Nitrox Cert cards pretty much fill it up, so I think your item is too thick.