This magazine is designed to be compatible with SIG Sauer Mosquito's chambered in .22 Long Rifle and containing 10 rounds of ammunition. The magazine is made from high quality aluminum and features a matte black finish. The most important aspect of this magazine is the fact that it is made by Sig Sauer so you can rest assured that the magazine will meet and exceed the specifications and tolerances set forth by the factory engineers. You can be all but certain that this magazine will fit perfectly and function flawlessly the same as with the magazine(s) that shipped with your firearm.