Round M2 copper knurled column security copper monitoring pass stud double column camera Length12MM stud head round double Round M2 copper knurled column security copper monitoring pass stud double column camera Length12MM stud head round double Round M2 copper knurled column security copper monitoring pass stud double column camera Length12MM stud head round double Round M2 copper knurled column security copper monitoring pass stud double column camera Length12MM stud head round double Round M2 copper knurled column security copper monitoring pass stud double column camera Length12MM stud head round double Round M2 copper knurled column security copper monitoring pass stud double column camera Length12MM stud head round double Round M2 copper knurled column security copper monitoring pass stud double column camera Length12MM stud head round double Round M2 copper knurled column security copper monitoring pass stud double column camera Length12MM stud head round double