This company in Germany offers a cell upgrade against the well-known problem of Rolleiflex 600x batteries loosing their ability to remain charged. Price is 38 (~$49) incl. doing the work and they seem a qualified battery seller. The eBay DIY kit is $39, so it is quite attractive. http://www.akkuline.de/2757_AKKULIN...r-rolleiflex-rolleiflex-slx-zellentausch.aspx Site is in German. No relation, just a discovery. Have not used them, but comments on the site and German forums are positive.