Pretty much impossible to find one lately - This unit works with the first model GX680 and the GX680 II. (Does not work on the GX680 III other than as a finder only.)
Very good condition with the normal amount of dust inside since they are not sealed.
No damage to the optics that I can see. Recently tested on a first and 2nd model body, very accurate. Provides TTL flash metering also.
Price dropped to $335 plus shipping - payment by Paypal - shipping only to verified address, or I can run a Visa/MC or Discover through the business account where I work. No charge for PayPal or Credit Card payments. Will also accept USPS Money Orders.
Listing soon - Three bodies - a GX680 1st model, GX680 II and III, and a bunch of lenses. I am moving to the Pentax 645Z.