QHYOAG is a thin and solid design. The OAG main body is just 10mm thick. Adding an M42 thread or M54 adapter ring adds only 3mm for a total thickness of 13mm. There are six 3mm through holes in the OAG for direct connection to the QHYCFW and QHY A Series cameras
There is a focuser in the QHYOAG. It is for the focus adjustment of the guider. There is a thumb to lock the position. When focusing please loose this thumb. After focusing get well , lock it. Please do not move the focus ring when in lock status to avoid the damage. When it is locked, you will still find the focus ring can be rotate a little. This is normal and the focus is not changing.
The light patch hole of the QHYOAG is 7mm for the guider camera.