DC 3.7V 220mah 402030 Rechargeable Lithium Polymer Replacement Battery for DIY 3.7 5V Electronic Products with Built in 2 Wire Replacement, Bluetooth headset, watch

This battery is applicable to electronic products with DIY 3.7-5V less than 0.814Wh 220mAh.（ Not applicable to high-power electric tools and model aircraft） Please note that connector specifications and polarity are based on the product display image. The red wire is the positive terminal “+”, and the black wire is the negative terminal “-”. Do not reverse the connection! Some products' original batteries may lack plugs, have incompatible plugs, or exhibit mismatched polarity. No worries—you can simply cut the wires and use the included heat-shrink tubing to connect the wires of the same color from the old plug. 402030 rechargeable lithium ion polymer battery, nominal voltage 3.7V, full charge voltage 4.2V, capacity 220mAh, power 0.81Wh, size 4×20×31mm(0.157×0.787×1.22inch）(T*W*L), Weight:5g(0.176oz)，Maximum current:0.2A。 It can prevent overcharge, overdischarge, overcurrent, and short circuit. It‘s consists of of large-capacity A+ lithium battery, Japanese Seiko IC overcharge and overcurrent short circuit protection board, 3302-26 high temperature resistant silicone cable, and genuine JST Pitch1.25mm 2-pin connector module. If any quality issues arise within one year, please feel free to contact us sellers for a replacement.