VersaPlanetary Integrated Encoder question

[trycatch]

Just a trying to get a quick clarification about the VersaPlanetary encoder - I see it's the magnetic encoder.. it *looks* like the magnet is built into the top gear that's rotated by the thru-coupler, so you don't have to bore a magnet into an axle like if you were using just the encoder by itself.

1. Am I understanding this correctly? It looks straightforward but I want to be sure.
2. Is there a way to get one of these gears by itself? We have a couple of the encoders by themselves, it would be great to be able to 3D print an encoder to go with it (as a cool "making something yourself" experience for the students.) I'm not sure where or how you'd find a gear like this though.

Thanks everyone!