You can't go wrong with Glock OEM magazines. They have withstood the test of time.
Glock G/17 Magazine 17 RoundsManufacturer: Glock Inc.
This is a factory 17-round magazine for Glock 17 pistols
These 17-round standard magazines feature a flush-fitting baseplate and numbered witness holes for keeping track of capacity. They’re engineered for optimum fit & function, and designed to drop free when released.
ONLY fits 9MM ammunition. Use in Glock 17 pistols or in a Glock 26 or 19 for extra capacity.
Glock magazines come with a very strong spring rate from the factory to ensure reliability in the toughest of conditions. Sometimes, magazines are found to be a little bit difficult to load at first. However, after a few times loading and unloading, the springs break in nicely and it becomes much easier to load.