 - Alpa Metrology FA235 (FA2354545)- Manufacturer: Alpa
 - NO GO metric coarse pitch (M) threaded rings ALPA FA235 In hardened steel. Tolerance 6g. Pontoglio, Italy
 - Alpa Metrology FA230 (FA23061)- Manufacturer: Alpa
 - GO metric coarse pitch (M) threaded rings ALPA FA230 In hardened steel. Tolerance 6g. Pontoglio, Italy

