The rival arms mag baseplate increases weight at the bottom of your glock magazine and aid in faster magazine changes as well as adding felt weight.It effectively reduces felt recoil and creates a more balanced firearm.The plate is cnc machined from aluminum with a hard anodized finish.Note: this model is not compatible with glock 36,42,42,48 models.Caliber: 9mm LugerFinish: AnodizedModel: Mag BaseplateMaterial: AluminumModel Fit: Glock Except 36,42,43,48Brand Fit: Glock