A 4" lens barrel and board arrived today - anyone guess what it actually is?

Also some 110mm lenses arrived, they are 4 dioptre and are over 4" wide - I will be getting a wider barrel and board made up to fit them, they are 4 dioptre lenses (although they are double convex so not ideal) but I will try and see what they are like stopped down

Steve also very kindly sent me some bellows, the front of a larger set has a 4" hole which I will perhaps look at building a front standard for as well.

Things seem to be progressing quite well so far, I will see how much progress I can make on Saturday, hopefully the macro slider rail will arrive soon so I can attach the standards etc.