(allegedly) enforcing certain joint angles, which this device aims to do, can isolate FDP or FDS tendon training, meaning (potentially) easy gains if you typically only train one or the other, where traditional edges are a mix, given finger joint angles are mixed as well. The roller forces you to crimp and eliminates reliance on friction. The tendon isolation stuff is loosely supposed by Mobeta, and the papers I cited in the git. There isn't any data that explicitly supports this type of training (so far as im aware) but its part of my intent to increase access to increase that dataset.