This is the Mec-Gar Sig Sauer P320 9mm +4 magazine extension.

Upgrade your factory Sig P320 magazine with this high-quality +4 extension from Mec-Gar!

Designed for use with full-size factory Sig P320 magazines, this extension comes with everything you need to increase your capacity with ease. Featuring a heat-treated phosphate steel locking plate and a polymer extension, its durability and drop-resistance are unmatched.

Whether you’re heading to the range or defending your home, you can never have too many rounds! 

Grab a few of these extensions while they are still in stock!