Blue Diamond Paint waterman but HT-BC has a similar

but HT-BC has a similar shape and is better suited for the smaller hard rubber sockets and it's less likely to cause breakage in hard rubber

From The Fountain Pen Shop in Monrovia

EACH PEN HAS A PAPER NUMERIC LABLE PUT ON BY PARKER

All grey bodies with colored trim

This piece is completely un-marked except for white tape hand printed labels presumably used for tracking this design through some sort of test regimen or evaluation

Blue Diamond Paint waterman but HT-BC has a similarPARKER BLUE DIAMOND PAINT. Restore the paint on blue diamonds with this oil based enamel. Be advised that many parker pens DID leave the factory with un painted blue diamonds on clips. But if you have damaged or chipped paint and want to repair the blue diamond on your clip, or, in the case of first year desk pens, on the barrels, this will do a nice job. This oil based paint will cure to a tenacious, rubbery coating. I apply it with a toothpick, let