"Paul Reynolds' Wrist Rascals are a fantastic tool for developing proper hand position, perhaps the single most crucial element of a solid left-hand technique. Highly recommended! - James Ehnes, Concert Violinist
Build a Strong Foundation
Corrects collapsed, "pancake or pizza-pan" wrist.
Trains the 4th finger to stretch up to the correct placement.
Strengthens the muscles of the hand, specifically the too often neglected front portion responsible for keeping the 3rd and 4th fingers over the fingerboard.
Comfortable. Simply a foreshadowing of the hand being closer to the body as it will be when shifting begins.
The Wrist Rascal is a training device that should be used on and off, as with any other training tool, so that it doesn't become a crutch.