J.....
This is the 1.75" mold. Others here may prefer the 2.25 and 2.5 but those persons are generally from further south. It will be only a matter of which size you want, but the methods I have described will work in any of them as well as just about any other mold that has a top and bottom definition. I'll go out on a limb here and say that I think every crappie angler on this site has one or more of the small fry molds in one size or more.
In addition to catching fish of all kinds, the small fry baits are the easiest to use out of the wrapper of all of the molds I own. I have NEVER had an issue with this bait or the mold. The small fry baits are hands down the easiest for the novice to master and learn to manipulate colors with. If you want to seriously expand your abilities to handle and master plastic bait injection, I would put one of these molds at the very top of your list and hand that list to every living relative you have as a birthday or Christmas gift suggestion or for just being a good guy gift suggestion.