This replacement magazine spring fits factory original Sig Sauer magazines of German origin. Using factory replacement parts guarantees excellent fit and reliable operation. This particular spring fits the following models:P226 9mm 15-Round
P226 40 S&W 10-Round
P228 9mm 13-Round
P229 40 S&W 12-Round
Sig Sauer magazines, magazine springs, and magazine bodies are either manufactured in Italy or Germany. German made magazines have a zipper style weld while Italian magazines have a flush fit as the weld is made on the inside of the magazine body. A German magazine body will only accept a German spring, likewise an Italian magazine body will only accept an Italian spring.