The Starwave 7.5mm T-Thread extension tube has a male and female T2 thread on each end.
A special "Easy Grip" scalloped outer ring makes the extension ring easy to tighten or loosen to reduce sag between your camera and telescope, even with gloves on.
It can be attached to T-Thread DSLR camera adapters, or stacked with other T2 extension rings to fine tune the distance between camera and flattener. By stacking, various spacings can be achieved..
A 2" OD barrel (excluding the scalloped Easy Grip) allows the spacer to be inserted into a 2" eyepiece holder.
Extension or spacer rings help you achieve the required backfocus for imaging with CCD and DSLR cameras.