Topeak PanoBike Heart Rate Moniter TPB-HRM01

Battery CR2032 x 1 (included)
Battery Lifetime (Approx) 900 hr
Fit Chest 70 - 120 cm / 27.5??- 47.2??br>With chest strap extension (optional) :
 100 - 150 cm / 39.4??59??
Tech Bluetooth® Smart super low energy technology
Transmission Range < 5 meter (16.4 ft)
Weight 32 g / 1.13 oz (Strap)
 14 g / 0.49 oz (Monitor)
Waterproof IPX 5