LabToad Timers and Calculators
LabToad is the most versatile, complete, and beautiful timer and calculator application you'll ever find!
Simple enough to be used at home and powerful enough to be used in the lab. Features count up, count down, and alarm timers. Supports email/text messages. LabToad has calculators for molarity, molar masses, C1V1 and A:B dilutions, unit conversions (500+ units), and more. Also see LabToad Timers at a cheaper cost from Cryofrog.