Wolff Extra Power Magazine Springs for the Glock 17, 17L, 20, 22, 24, 31, 34, 35 are used when magazine reliability is critical or when original factory springs have lost their tension. These extra power springs put more pressure on the follower, presenting the cartridge to the slide with more force. DISCLAIMER: This product is not manufactured, authorized, endorsed, or warranted by GLOCK. GLOCK does not warrant or represent that this product is compatible with GLOCK pistols.