GEONAUTE Onrythm 50 - Waterproof Pulse Meter Heart Rate Monitor Watch with Chest Band Strap. Stopwatch for Cycling Running Fitness The easiest heart rate monitor for athletes in BPM (Beats Per Minute). Simple Stopwatch and chronograph Essential cardio features. User-friendly menus and easy browsing Black HRM - Heart Rate Monitor chest strap belt included Waterproof: Watch: 5atm (swimming) - Belt: 1 ATM (water splashes) BATTERIES: Watch: CR2032 included - Strap: CR2032 included