Anti-tilt follower, steel reiforced feed lips, steel floorplate, and some of the nicest springs found on any AK magazine, these were purchased as mil-surp/overrun, and are brand new, unused.
Search under "identifying various types of AK-47 magazines" for further information on these excellent polymer magazines. 
I have ten of these available for sale @ $11 each, or ten for $100.