Used: Rolleiflex 90 degree "t" style viewfinder for 6000 series cameras
The T-finder is a 90 degree viewfinder which has an telescoping front eyepiece that can be pulled out to increase the magnification for easier focusing. It also has an adjustable diopter on the eyepiece which is quite convenient. They are also lightweight since an lens and mirror is employed as opposed to a big blog of prism glass. This one is in very nice condition too. I don't find them very often - I think I've only had three of them over the years. This one is in excellent condition overall with just a few tiny cosmetic marks on one side.