This replacement or spare magazine is compatible with your S&W SD. It is constructed of heat treated steel with injection molded mag follower and mag spring formed from chrome silicone wire. Made in the USA.
Specifications:

Caliber	9mm Luger
Capacity	17
Finish	Blued
Model	S&W Self Defense
Material	Steel
Type	Detachable
Model Fit	SD9
Brand Fit	Smith & Wesson
Max Capacity	17