S&W- N Frame (medium-large) revolver frame, square butt
Model: 20, 21, 23, 24, 25*, 26, 27, 28, 29*
Model: 57, 58, 520*
Model: 610*, 624
Model: .44 Classic Hunter
*= There is both a round butt and square butt version for this model. So please determine whether your pistol is round or square butt.