Stringvision Bowgrip Carefully designed as an elegant anti-fatigue bow covering for the string player, the Stringvision Bowgrip offers an unprecedented level of comfort and ergonomics for the string player. One model stretches over violin, viola, or cello bows of all sizes without removing the frog. Yes- the height of bow frogs is very consistent, (even on incremental size bows) so one size truly does fit all bows. Stringvision Bowgrip is easy to slide on. All bowgrips have a light coating of (bow friendly) cornstarch on the inside. This makes installation of the Bowgrip quite easy. Simply take it out of the package and "work it" over the frog. The fit is very secure, and the bow grip will stay in place. The bowgrip’s thumb indent (now reinforced) allows curved and comfortable thumb placement. Additionally, this product will protect any bow from wear, and since the bottom corner of the frog is covered by the grip, this will also help to avoid minor nicks to the bouts of the instrument.