The Kardan Color is based on the Technika so bellows, standards, etc don’t interchange with the Bi. But many parts will interchange with the Kardan Color 45s. Look up google images and you’ll see how different they are. The 45s is often crazy cheap on eBay and you can get backs, lens boards, bellows etc that will fit your Bi, which is also quite the bargain for such a sophisticated 4x5 monorail. Speaking of ground glass, I picked up a very nice one with a fresnel from one of the Chinese sellers on eBay. Much brighter than the original screen. I really don’t know why the Linhof monorails are so inexpensive, the quality and engineering is of the highest order just like their more popular cousins, the Technika line.