I purchased 2 orders of the +2 extensions not knowing they come in sets of 2. I put them on my 13 Rnd Glock 21 mag, but only gotten 1 extra round in. I have four +2 extensions on 4 different mags and can only load them to 14 not 15! I contacted Cheaper than dirt's customer service and was told I would be refunded cause they have gotten many complaint of this. I guess 14 rounds are better than 13, I guess you are supposed to count the 1 in the chamber! lol!

I put these on my back up, a Glock 27, and only got 9 rounds in. I took them to a friend who happens to be a Glock certified armorer to see if I made a mistake. He looked at me and nodded, saying that these were a mistake when they left the factory. (Ever notivce there's no name on them? Well, I guess I wouldn't want to accept responsibility for these either!) According to him "NEVER put anything on a Glock handgun that doesn't have GLOCK stamped on it." Bought the real deal Glock part on ebay, and they work just fine. In fact, I have them on ALL of my duty mags for my 27 and 35. Now, to have a word with Uncle Gaston about those floor plates...

it comes with 2 in a pack but i tryed puting them on my new mags and my old mags and its only +1.

It seems some magazines are only increased by one capacity and not two so be advised.

I didn't realize these come in sets of two. Each order has two extensions. That was a nice suprise. They were extremely easy to install. However, once you have them on, getting them off is a different story. I bought these for my Glock 21. I have high cap mags that hold 13, so + 2 would be 15. But, when I put them on the mags that came with the glock, it would only fit 14. Trying to force 15 caused breaking sounds. I have two other factory glock high cap mags that I bought and they work just fine on those, and they feed in pretty easy. Other than that. I enjoy having the extra round or two.