CMMG Tri Lug Mount Defcan 9 9mm 1/2 - 28 Nitride - 99DA587. Specifications for CMMG 99DA587 Trilug Mount Decan 9mm 1/2"-28 Nitride: Manufacturer: CMMG Finish: Nitride Length: 1.44 in CMMG 99DA587 Trilug Mount Decan 9mm 1/2"-28 Nitride