Warne 3306 Magazine Extension Black, +3 (9mm Luger), +4 (40S&W), for S&W M&P 9/40 Apparel It has a glass-filled nylon

It has a glass-filled nylon (GFN) handle that is thin and ergonomic

It makes mounting an optic to an AR-style rifle very easy

They can be used on metal

but need more space for accessories

The replacement spikes have a simple screw on design for the SR-5 Bi-Pod that allows you to quickly change from rubber feet to steel spikes in seconds and provides aggressive traction on dirt or any soft surfaces

Warne 3306 Magazine Extension Black, +3 (9mm Luger), +4 (40S&W), for S&W M&P 9/40 Apparel It has a glass-filled nylonThese extensions feature an ergonomic shape that allows for better insertion, and finger grooves, allowing the magazine to be stripped from the handgun if needed.