The Medium Off-Axis Guider by QHY has 47 mm to the center point. It is a thin and solid design only being 10 mm thick. Adding an M42 thread or M54 adapter ring will add 3 mm for a total thickness of 13 mm. There are six 3 mm through holes in the OAG for direct connection to the QH-QHYCFW2 and QHY A series camera.
The prism position can be adjusted and can be locked down to fix its position. The prism is 8 mm x 8 mm size and the aperture between the prism and mirror is 8 mm in diameter. The QH-QHYOAG has a multi-thread 1.25-inch focuser build in which has a locking thumbscrew to hold the guide camera after focusing.