Smith & Wesson K frame thumb piece early style, blue $35.00 Part 21 on the exploded diagram. Used, excellent condition blue thumb piece, early style, from a 19-4, K frame revolver. Will fit other models of K frame revolvers. Only 1 left in stock Smith & Wesson K frame thumb piece early style, blue quantity Add to cart Category: Smith & Wesson Related products Smith & Wesson K frame Yoke, old style with gas ring $100.00 Smith & Wesson K frame mainspring $15.00