SVBONY SV238 Off-Axis Guider(OAG) delivers precise,reliable astrophotography performance. Direct connection to deep-sky cameras with M2.5 holes (noticed back focus). You can also connect to filter drawers (SV226 M54&SV226P);Compatible with ZWO/ToupTek New motorized filter wheel(with screw holes). SV238 connects to cooled cameras with 2 methods:1.Direct connection to M2.5-hole cameras with self-provided extension tube/T-Ring is required to achieve 55mm back focus 2.Connection via filter drawers/filter wheels(with holes); confirm compatibility by hole parameters in SV238 mechanical drawings. SV226P M42-M48 Filter Drawer for OAG Version, New Upgraded with Twelve M2.5 Female Threads, Photographic Filters Drawer, Double Magnetic Filter Holder for 1.25" and 2" Filter, filter drawer featuring the anti-light-leaking design that can effectively solve the light leaking issue under long exposure. The product is designed as a perfect circle, with a simple and beautiful appearance and good surface. Two pairs of strong magnets are used to achieve strong adsorption. 2-in-1 design, can use offilter1.25" & 2" specifications on the market. Meanwhile, by optimizing the threaded opening, it has been improved to have better OAG compatibility.