... regular nut and flanged nut7. Standard: BS1139&EN74 Class A&B8. High Quality Forged Coupler We are leading company engaged in scaffolding ... and pressed scaffolding couplers/clamps, such as double/fixed coupler, swivel coupler; fixed/swivel beam/girder coupler, putlog coupler, plank coupler, sleeve coupler, joint pin, single coupler, etc ...