This is the HK CC9 9mm 10-round magazine. 

These genuine ten-round HK CC9 magazines provide the ultimate concealability while keeping your capacity in the double digits.   

Constructed from stainless steel and finished with a durable black oxide coating, these magazines won’t skip a beat during extended range sessions where they are getting dropped or thrown around. Inside, you’ll find a bright red anti-tilt polymer follower that keeps each round feeding smoothly. 

Not that you’ll have much trouble keeping track of ten rounds, but just in case, there are rear-facing numbered witness holes. These features make this magazine ideal for concealed carry, but you’ll likely want a few spares given the lower capacity.  

Grab a few spares to ensure you don’t short yourself on potential capacity!