Ymddangosiad bollt maint safonol dewisol: GB/T5783, GB/T5782, SH/T3404, DIN933, DIN931, ISO4014, ISO4017, UNI5737/UNI5739 safon Eidalaidd, ASME B18.2.3.1m, ASME B18.2.3m.3.3. .5m hecsagon allanol metrig B18.2.3.6M, ANSI/ASME B18.2.1 a dimensiynau safonol eraill.