I recently picked up 4 mags to get 2 I wanted for my Erma kgp-69 luger. I am sure one of the other 2 is for a Erma ep, la, or et mag. The last one has me baffled. It is about 3/4" longer and has a sq mag catch hole vs the rectangle on the other one and is on the opposite side. The KGP has a 1/4 rd mag catch hole. I am thinking the 4th one may be for a stoeger or? The Ermas held 8 rounds and the Stoegers 10. There was also an artillery model made by one of them. I will try to post pictures tomorrow. Hopefully somebody may know something. Thanks, Mark