Common sandblasting air fittings are 1/4" quick disconnect fittings in both industrial and ARO style are used on PPE and small components. 1/2" quick disconnect Thor style fittings are popular for small machines. Chicago fittings are the most popular air fittings for sandblast machines. 2-lug Chicago fittings are used for one inch or smaller lines and 4-lug Chicago fittings are used for larger lines. Another common fitting is the ground joint or spud ground joint fitting, these fittings are typically for larger equipment.