This is a brand new OEM Sig Sauer P229 .22LR Threaded Barrel. You can use this barrel to convert your P229 already chambered in .22LR with a non-threaded barrel. This will NOT convert a P229 in 9mm, .40S&W, or .357 SIG to .22LR (you will need a Sig Sauer Conversion kit to do this).
Note that it is not uncommon for barrels to need fitting. We recommend having a gunsmith perform this.