3M 45179, Roloc Disc Pad TR, Medium 4 in 1/4-20 Internal, 7000045281 
Insize 2187-146, ADJUSTABLE SNAP GAGE, 5.47-5.75″, 6928640314582
$399.45
Used as Go/No-Go gage by setting upper and lower limits.
Flatness of anvil: 59_in.
Parallelism between tips and anvil: range 0-1.26″: 118_in,
Related products
Measuring/ Inspection Instruments
Insize 0213-A500, INFRARED THERMOMETER, -58?F~716?F/-50?C~380?C, 6940561934700
$79.29
Measuring/ Inspection Instruments
Insize 4809, U.S. STAND SHEET METAL GAGE, 0-36(.3125~.0070″), 6928640330162
$35.18