Peacock 20-377 Dial Bore Gage
Covers bores in the 2"-6" range, is an essential tool for professionals, particularly engine builders.
This is new old stock.  I purchased this new in 1993, (I paid $177, the equivalent of $400 today), but never ended up using it or even taking it out of the box. 
• Includes Multiple Measuring Extensions 
• Dial Range: 0.0001"-0.050" 
• Original Wooden Storage Box 
• Made In Japan 
• Durable construction
• Easy-To-Read Dial