HP 50g Graphing Calculator - Manual (Page 160)

Page 3-30
The soft menu keys corresponding to this CONSTANTS LIBRARY screen include
the following functions:
SI when selected, constants values are shown in SI units
ENGL when selected, constants values are shown in English units (*)
UNIT when selected, constants are shown with units attached (*)
VALUE when selected, constants are shown without units
STK copies value (with or without units) to the stack
QUIT exit constants library
(*) Active only if the function VALUE is active.
This is the way the top of the CONSTANTS LIBRARY screen looks when the
option VALUE is selected (units in the SI system):