Sinclair Wrist Calculator

I was looking up the name of a game that I used to play on my Sinclair ZX-81 when I was kid. That was also awesome, tape cassette storage media! Go Tape Cassettes FTW! But I stumled across this gem, which I was not aware of. The master of small, Sinclair was. It cost about $20 in 1977 and here are the specs.

• Display is 8 digits, red LED.
• 4-functions, %, memory, square root.
• 8.1v (6x mercury cells).
• Integrated circuit - Mostek MK50321N, here date coded mid-1976.
• 47 x 45 x 18 mm (1.9 x 1.75 x 0.7 ins).

I would have killed for one, to round out my ubernerd persona in grade school.