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 Sight Drifting Punch $15.97 S&W 6904/4006 series XP magazine springs 3 pak $34.97