3.7 Volt Rechargeable Battery, REACELL 3000mAh Rechargeable Battery, Button Top NiMH Battery High Power Long Lasting for Headlamp, LED Flashlight, Solar Light, Electronic Devices etc (4 Pack+Box): Amazon.co.uk: DIY & Tools
RS PRO 3.7V Lithium-Ion Rechargeable Battery Pack, 7.8Ah - Pack of 1 | RS
ICR18350 Rechargeable Battery 3.7V Li-ion 900 mAh Batteries for Torch, Toys,Pack of 4,PKCELL: Amazon.co.uk: Electronics & Photo
All you need to know about the 3.7V lithium ion battery-Tycorun Batteries