The ACC06 2" adapter plate provides a 3" eyepiece barrel interface. It is directly compatible with many third-party large format focusers. Aluma AC, STXL, and STX cameras have a standard mounting bolt pattern (four 6-32 threaded holes on a 4" diameter). Please know that a high quality focuser should be used to ensure that the weight of the camera and accessories is well supported. It is recommended to use at least 3 grub screws t ensure the camera is sturdily mounted. This plate is 0.2" thick.