Accessory Collar The BT5952 is a ø38mm Accessory Collar from B-Tech’s System V Range; a collection of components designed for the installation of CCTV and other ceiling mounted equipment. Designed for use with BT5935 ø38mm poles, the collar features dual fixing points for single or back-to-back installations and enables interfaces such as flat screen mounts to be attached to poles, allowing professionals to customise ceiling mounted security solutions to their specific requirement.