This is a variable eyepiece projection adaptor with a male T-Ring at the camera port and a female T-Ring or 2-inch barrel at the telescope port. The unit can house quite large eyepieces. It is typically used with a DSLR camera and where additional magnification is required for planetary imaging. I purchased the unit in 2014 but never used it, as I moved away from DSLR cameras to cameras with small sensor chips.
The price is $136 (about half the price of a new unit) excluding package and posting. Preferred payment is by EFT to my BSB account. I'm located in Lindfield, Sydney if you prefer to pick it up. Please contact me using the forum's private messaging.