Urrea sockets have a super-Drive design that prolongs its life and does not damage the screws and nuts and bolts. Urrea sockets have a resistant phosphatized to finish recommended in case of FOD (foreign object detachment). It is recommended to use sockets with phosphatized finish prevent the shedding of coating particles. Urrea products is reinforced by showing an indelible and permanent mark with the country of origin. This meets ASME / ANSE norms, as well as rules established by the federal Trade Commission in the United States. Opening size: 21 mm. Type: II. Length: 3-3/16". Nut end outside diameter: 1-1/4”. Drive end outside diameter: 1-3/16”. Nut deep: 1-1/2”.