HCW 553 RC Mini Shaft Quadcpter 20C 3.7V 350mAh Li-Po Battery

These were extra batteries in a quad-copter to extend play time :-)

It worked for my application.

Great product! Used this battery to replace a smaller one in my rc heli. Much longer flight time. I'm very satisfied.

I bought this for a  World Tech Toys X-Quad 2.4GHz 4.5CH Gyro Electric RTR RC Quadcopter . The original batteries are 300mah and do not really fit well into the battery bay on the quadcopter; they are too thick making it hard to get in an out. They are also considerable shorter than the length of the battery bay. This battery fits much better and has an increased capacity of 350mah.About LiPo battery physical dimensions=============================Many LiPo batteries are labeled with the physical size using a standard format, you just need to understand that format so you can buy the right size. On this battery you can see the size is labeled as 702035. The way to decipher this is as follows.702035 = 7.0 20 35 or fully expanded702035 = 7.0mm height x 20mm width x 35mm depthNote that the height seems to always be stated in 1/10th's of mm.As another example the original batteries that came with the  World Tech Toys X-Quad 2.4GHz 4.5CH Gyro Electric RTR RC Quadcopter  are 752030. 752030 = 7.5mm height x 20mm width x 30mm depthSince these batteries were slightly too thick and should have been a bit longer I replaced the 752030 with a 702035; .5mm thinner, 5mm longer.

These have worked out great for my Ladybird and at a great price.