used been kicking about amal 376 Monobloc / 600 series concentric threaded ring for air filter or air filter hose to push over alloy 13.5 mm length internal dia. on thread = approx 40mm external dia approx 47.5 mm with a thin lip of 51 mm but may work with other makes enfield panther norton ariel ajs matchless triumph Carb shown is NOT included , to fit triumph triton tribsa BSA norton sunbeam PANTHER ARIEL AJS MATCHLESS velo etc etc ,
