The manufacturer Bob's Knobs supplies various collimation screws for Schmidt-Cassegrain, Ritchey-Chrétien and Newton telescopes .
The selection includes screws for primary and secondary mirrors for optics between 5 "and 16" . In addition, Bob's Knobs offers mounting screws for various mounts from Celestron (CGE, CGE Pro, NexStar), Losmandy (GM-8, G-11) and TeleVue (Gibraltar).
Please note the respective specification and technical data to find the right screws for your model!