Designed as an anti-fatigue bow frog covering, the Stringvision Bowgrip offers an unprecedented level of comfort and ergonomics for the string player. If you are a string teacher, you've probably heard that it makes teaching a student how to hold the bow a lot more straightforward, as a thumb indent allows for curved and comfortable thumb placement.
Stringvision Bowgrip is quick and easy to install without removing the frog. The bowgrip stretches nicely, so simply take it out of the package and patiently work it over the frog. The fit is very secure, and the bow grip will stay in place. The grip fits well over incremental sized bows (3/4; 1/2, etc.) as the height of these frogs is very consistent with full size frogs.
Stringvision bowgrip even protects instruments and bows!
• This product will protect fine bows from wear around the frog- especially the thumb area.
• The bottom, inside corner of the frog is covered by the grip, which will help to avoid and nicks to the "c" bouts of the instrument when down-bow collisions occur.
Stringvision bowgrip is made of a long lasting, high-tech elastomer which is specially formulated as a grip material. It's non-latex, and FDA approved. You'll probably find that it feels like something that is meant to be gripped and finessed without undo strain. You'll also likely notice that the bow hand and arm will not fatigue after longer playing sessions.
(From the StringVision website)