APF Mark 40 Electronic Calculator

I found this really cool vintage calculator at one of my local shops i stop in often with box and manual. Still works great.

Here is some info about it:

Manufacturer: apf

Model: Mark 40

Year: 1975

Form: Pocket

Functions: Basic four, constant, %

Number of Digits: 8

Display Type: LED

Logic Technology: LSI

IC Complement: Mostek MK50282 N | Toshiba T1347

Batteries: 9V

Power Connector:9 VDC, + tip, sub-mini audio

Source: http://www.cs.ubc.ca/~hilpert/eec/calcs/apf40.html