This vintage QA-100 Time Face Pocket Time Calculator has the unique capability of doing time calculations.  It can add or subtract hours, minutes, and seconds, and can also convert time into decimal form, for example 3.8 hours. This is a useful calculator for people in video or audio production, disc jockeys, pilots, and dispatchers. 

This calculator's other features include, addition, subtraction, division, multiplication, built-in analog and digital clock, % percent, square root, timer, alarm, 12 & 24 hour option, memory functions, and date (see photos of keyboard).

This calculator is in very good condition (see photos).  The battery compartment is clean and complete free of corrosion (see photos).  It was made in Malaysia and uses a CR2025 battery.