It would depend on the caliber of your P220 - the P229 is available in 9mm, .357 Sig and .40 S&W.
Different Sig Sauer models and calibers come with different sight heights to achieve proper point of impact at 25', depending on the caliber.
This product is intended for use with the 9mm and .357 Sig models.
If your P220 is .40 S&W, you would use the Trijicon SG103O (orange surround) or SG103Y (yellow surround).
All P series and SP models use the same dovetail mounting front and rear with the exception of the P250 which has a different rear sight mount configuration (same front sight as others), and Trijicon specifically excludes the P938 for this product.
9mm and .357 SIG use #8 REAR / #8 FRONT
40 S&W and .45 ACP use #8 REAR / #6 FRONT
Mark H.