new been kicking about amal 376 Monobloc and 600 series concentric threaded ring for air filter or air filter hose to push over light weight alloy 11.5 mm length internal dia. on thread = approx 40mm external dia approx 45 mm but will 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 ,
