$15.40VALBEL Battery Replacement for Suunto Spartan Trainer, Spartan Trainer Wrist Heart Ra, Spartan Trainer Wrist HR, Part No.: PR-352828, PR-402626P 3.7VAmazon- $138.19Gems PS75-40-4MNZ-C-HR Series PS75 Cylindrical Pressure Switch, SPDT Circuit, 150-650 psi Range, 1/4" MNPT Steel Fitting, RA DIN 43650A Male Half (Pack of 5)Amazon