This brass body mount washer is from T&S Brass. It measures 1-31/32" OD x 1-3/16" ID x 3/32" thick. T&S part number 002290-45.
See the #02001 Pre-Rinse Faucet Parts Breakdown
EC Part Number: #02274
Manufacturer Number: 002290-45
Manufacturer: T&S Brass and Bronze Works