Brand: SHARP
Model: EL-506H
Type: Scientific calculator
Picture: SHARP EL-506H
Batteries: LR44 x 2
Lifetime: Introduced: 1979
Terminated: unknown
Notes: Scientific calculator with statistic functions, hyperbolic functions and BASE conversions (Hexadecimal, hence the H in the type designation I guess).

Peter Vis has a nice write-up on this calculator, read it here (link valid 2024-01-13).

This calculator has the distinctive blue memory buttons (which I quite like) that are also available on the SHARP PC-1403, the SHARP EL-509D (and probably others).