Based on Ron Wisner's design of the 4 X 5. Relatively light, adequately flexible. Plenty good for what you have been shooting. Some accessories available - reduction backs, fresnel, lensboard reducer (which, for some reason, is also an extension, rather than a recessed board). Comes with a bail opening back which is nice on an 8 X 10. 30" + bellows draw if you cantilever the front out. They say you can squash it down to 90mm. Don't know about Calumet's service though. You're looking at used, right David? Wood, you could fix most of it yourself if it broke.