ex military stock, some are pink and some charcol black

but all the same dimensions

NSN 2530997388519

Also 1691529C2 and 1691529C1

essential dimensions are OD 48mm  ID 39mm depth 31mm

That's 1" 1/2 x 1" 7/8 x 1" 1/4 in old money

small additional number available