FN/FAL-M

20 round black Zytel nylon magazine for FN/FAL, 7.62x51 .308 cal. Metric pattern rifle

The newly designed FN/Fal magazine. 

(Now compatible with any rifle that accepts FN/FAL metric magazines)

How do I know if I have a Metric or Inch magazine clip?

Picture shown below with an example. 

Metric has a small ramp like block on the top back of the magazine. 

Inch has a small block on the top back of the magazine.