Another but no pic-http://forum.treasurenet.com/index.php?topic=342312.0 I don't know if your backmark is the same as this one but i've pm'd turtlefoot13 so maybe he can fill us in on that info. Or maybe fyrffytr1 can fill us in if you pm him.
6- WATERBURY BUTTON CO. * 1849-1965
7- WATERBURY BUTTON CO. *CONN.* pre 1965
8- WATERBURY COS INC CONN post 1965
9- W W W W (waterbury) modern
10- W.B. CO.
The backmark "Waterbury Button Co. / Conn" written in "plain block" (non-serifed) letters, without stars or anything else but a double-circle of dots, is Mid-20th-century, up to 1965.