Hex adder (hexadecimal stylus / rack adder)
Houston, Texas, USA
||3600-3 (catalog number)
9 1/2 x 1 1/2 x 1/8 in.
A stylus adder, similar to many inexpensive models except it is designed for base 16 arithmetic. Digits are marked as 0-9 A-F.
Gwen Bell artifact and book collection