Replacement magazine spring. Some fitting may be required.
140mm will work in factory high capacity magazines and with up to +4 extensions, in 38 Super, 40 S&W and 45 ACP
140mm is 11 coils, the factory spring is 10 coils. The 140mm will need to be shortened is when used in factory, flat bottom magazines with shortened grip frames like the P13
The 170mm spring is basically for use only with 170mm competition magazine extensions (same three calibers as the 140mm)
Neither of these springs will work with 9mm Luger models
Replaces worn stock magazine springs for better performance in loading and unloading
Some fitting may be required