GKN Shardlow Internal Micrometer set. I think this might be made up of different sets as the attachments don't all line up to full inch measurements. Also the half inch spacer is missing. The shortest piece is homemade and doesn't fit very well. The range is 2.3inch to 11 1/2 . It would be better to use it as a comparator set. The thimble runs smoothly. Comes in a hardwood tray.
eBay