The hoop is made of PVC and comes with 6*20mm long screws.
The tail of the screw is a hexagonal screw, which is less likely to loosen than slotted screws and cross screws.
It is equipped with a matching small wrench, which can easily solve the instability problem of the main mirror without drilling holes and tightening screws on the main mirror. Connected with the dovetail plate, it is very practical and convenient to place the primary mirror on the equatorial mount.