Goosky S1 300mAh 2S 7.4V LiPo Battery – GT030039 (S1 V1/V2)

Convenient but difficult

Batt. holder is easy access and open to the air (good), but plugging and unplugging is very difficult (concerned it will tear my fingernails

Perfect!

Needed 5 more to round out a dozen! Getting lots of flights in!