Stop Collar API Casing Hinged Stop Collars For Oilfield Drilling Equipment Stop collar Stop collar is used to hold centralizers or cement baskets on any position casing, which ensures the position of centralizers or cement basket to meet the design, the stop collars are available in two types hinges type,slip on type, the stop collars can be installed on casing to limit the axial movement of centralizers and cement baskets. Usage 1. Fastening screw stop ring when use, first