I have something similar, got the Chirp wheel back in the day, loved it enough that I upgraded to the Chirp Wheel + when they released that. Would I recommend getting just one Chirp Wheel + for the spinal groove for $60 for the same size or less for a smaller one? Yes. Does this seem like a good choice if you’re trying to get your IRK paid for? Also yes, if you ever have back/shoulder stiffness.