I have a Zeiss 21mm viewfinder for trade. It comes without the box, but otherwise it is in perfect condition. Asking price is 275 Euros + shipping. I pay PayPal, and I'll deduct 5% if you want to pay by IBAN bank transfer.
I traded my 21mm lens for a 25mm, so not much need for this one.
DSC_0902 by sveinjarle1, on Flickr
DSC_0901 by sveinjarle1, on Flickr
DSC_0900 by sveinjarle1, on Flickr