4" XD recoil springs fit 4" XD pistols in 9mm, .40 S&W, and .357 Sig, and are available in 17 lb. factory weight or 19 lb. extra power. 5" XD recoil springs are for 5" XD pistols in .45 Auto only, and are available in reduced power 14 and 16 lb., factory 18 lb., and extra power 20 lb.
SPECS:
Recoil Springs - High-tensile spring wire. 4" XD fits 9mm, .40 S&W, and .357 Sig. 5" XD fits .45 ACP only. Guide rods sold separately and do not include extra power striker spring.
Catalog page 204