A home owner from Sarasota, FL says:
September 14, 2016
For Weathershield casement windows circa 1983. Made of some type of plastic. Weathershield no longer makes them.
Dave from SWISCO responded:
September 16, 2016
Take a look at our 55-175 Hurd glazing bead, which pushes down into the sash to lock in. Also look at the 55-186 Jeld-Wen bead, which pushes into the side of the sash to lock in. To be honest, it's hard to match up Weathershield parts. See if you could adapt either of these, though. They may be your best bet.