ASTM A320 vasega L 7 o se mea faʻapitoa mo noataga, studs, nati, ma isi faʻapipiʻi ua fuafuaina mo le siʻitia o le vevela vevela. ASTM A320 L7 vasega o loʻo vaevaeina i le 4 faiga faʻatino, a, b, c, ma d, taʻitasi ma le itupa eseese. Vasega 660 faʻapipiʻi e faʻaaoga i Belt Blilers, o le mamafa o vaʻa, paipa fugalaʻau ma alatoto mo le maualuga o le vevela o le tamaoaiga.