Sundials, Astronomical and navigational devices for predetermining the positions of heavenly bodies - namely, Astrolabes

SUNDIALS

ASTRONOMICAL AND NAVIGATIONAL DEVICES FOR PREDETERMINING THE POSITIONS OF HEAVENLY BODIES-NAMELY, ASTROLABES

Bracelets and wristbands impregnated with photochromic dyes that change color in response to UV radiation

Stickers impregnated with photochromic dyes that change color in response to UV radiation to warn the wearer when it is time to reapply sunscreen or to get out of the sun, for use in measuring UV radiation, not for medical use