The Generation 4 Glock 17 magazine holds 17 round of 9mm ammunition. This generation 4 magazine can be used in all 9mm Glocks, including gen 1, gen 2, gen 3 and the current 4th generation. The main difference between this generation of magazine versus the previous generations is that this magazine has magazine release notches cut on both sides of the magazine. The reason why is was done is because the generation 4 Glock have reversible magazine releases.
Although this magazine was primarily developed to be used by the Glock 17, it can also be used by other double stock 9mm Glock pistols. For instance, this magazine will also function with a Gen 1-4 17L, 19, 26, & 34. Of course, in the compact & sub-compact models (19 and 26), the magazine will extend past the end o the grip frame. However, this magazine will function perfectly in any 9mm double stack Glock pistol. This is a very useful feature for the concealed carrier. For instance, if you carry a Glock 26, you could also carry a spar 17-round magazine, instead of a spare 10 round magazine.
Glock magazines have a unique construction design. The magazines have a inner steel liner that is over-molded by polymer. This unique magazine construction allows the Glock factory magazine to be strong, durable, reliable, resistant to corrosion and resistant to deformation. The magazines also use a polymer base plate and follower.
The tension applied to the follower that pushed the bullet up is supplied by a steel spring. Glock uses very stout springs that supply a lot of pressure. By using strong springs, this ensure a long service life and smooth, reliable feeding. The springs in new magazines may be fairly stiff, making it difficult to load the magazine to its maximum capacity. If you experience this issue, it is suggested that you should load the magazine with as many rounds as you can and let it sit for a day or two. When you come back to it, the spring may have lightened up a bit to allow you to load the magazine to maximum capacity.
Factory Original Magazine
This magazine is manufactured by Glock. It comes off the same assembly line as the magazine that was originally supplied with your pistol. This ensures that this magazine is top quality and will fit and function with your Glock pistol.