From the cascara reference web page...
In fact the Groove Wedge can be mounted on any drum from 8” to 15” diameter and as an added bonus this means you can get the warm and woody vintage cross-stick sound on a 14” or 15” snare drum fitted with metal rims.
The Cascara Wedge is a deeper version of the Groove Wedge which allows you to play ‘cascara´ type Latin patterns on your kit. The Cascara Wedge can be attached to drums from 10” to 18” diameter.
I tried the groove wedge. Cool accessory, but overpriced.