Lithium ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of 150mAh for a total of about 0.6 Wh. If you need a larger battery, we have a full range of bigger cells The batteries come pre-attached with a genuine 2-pin JST-PH connector as shown and include the necessary protection circuitry. Because they have a genuine JST connector, not a knock-off, the cable wont snag or get stuck in a matching JST jack, they click in and out smoothly. The included protection circuitry keeps the battery voltage from going too high (over-charging) or low (over-use) which means that the battery will cut-out when completely dead at 3.0V. It will also protect against output shorts. However, even with this protection it is very important that you only use a LiIon/LiPoly constant-voltage/constant-current charger to recharge them and at a rate of 150mA or less. We suggest the Micro Lipo charger, which has a 100mA default rate.Like most lipos, the batteries we sell do not have thermistors built in. This is why we suggest charging at 1 C or even less - 100mA is a good rate, and available from any USB port if using a USB-powered charger Additional safety notes: Do not use a NiMH/NiCad/lead-acid charger! Also, do not abuse these batteries, do not short, bend, crush or puncture. As with all Lithium ion polymer batteries and with any power source - they should be used by experts who are comfortable working with power supplies. TECHNICAL DETAILS Weight: 4.65g Size: 19.75mm x 26.02mm x 3.8mm / 0.77" x 1.02" x 0.14" Power Lead Length: 127.5mm / 5" Output: 150mAh at 3.7V nominal Datasheet