Unfortunately, US customs does not allow to import batteries without devices. That's why you can use  these batteries in the US 

For Phoenixes 
https://www.amazon.com/Capacity-2600MAH-Rechargeable-Battery-Cameras/dp/B01LWY7YRN/
For AK12, AK15, AR15 and other guns 
https://www.amazon.com/Capacity-3100MAH-Rechargeable-Battery-Cameras/dp/B01LY96AB0/
For Hornets
https://www.ebay.com/itm/ICR-18500-2S1P-7-2V-7-4V-1600mAh-Li-ion-rechargeable-battery-with-PCM/272050367151
For RGB Headbands
https://www.amazon.com/Battery-Rechargeable-Lithium-Polymer-Connector/dp/B09F3BTMXT/