Magpul MBUS. You could probably use their "PTS" line since you have a .22. This is their import line of products that was made for airsoft and paintball usage, because the sights are cheaper and will not hold a zero to the recoil of a 5.56, 6.8, etc. However, because the .22 has no recoil, they would work fine. You should be able to buy a front and rear sight for $40. If you want the real deal, you are looking at $80-100 for a set, which is still relatively cheap for the quality you get compared to other brands (Midwest, Troy, YHM, etc).