MODEL: MG31 (Red Housing). (1) Snap-on MG31 Impact Wrench. ASSET TYPE: (1) OEM Snap-on 3/8" Drive Pneumatic Impact Wrench. Power Source: Pneumatic (Air). To insulate our operations, this exact unit'sSerial Number (06491119), anvil wear patterns, and housing casting marks have been logged in an unalterable digital archive prior to parcel dispatch.