For OMP Hobby M1, Align T15, 250 helicopters and any small airplanes, Gens ace 400mah 2s 60C 7.4V lipo battery perfectly is suited them and provided ultra-lightweight, low IR to your flying.
7.4V 2S 400mAh 25C High Rate Ultralight LiPo Battery for Micro RC Model Airplane Helicopter FPV Drone
HOOVO 2S LiPo Battery 7.4V 450mAh 30C Battery Pack with JST Plug for RC Helicopter Quadcopter Small Airplane Micro FPV Racing Drone 2Pack
Gens ace 400mAh 7.4V 60C 2S1P Lipo Battery Pack with JST-XHR Plug OMP M1
Gens Ace batteries have been proven within the Radio Control community to deliver reliable and consistent performance for all modelers alike. All Gens
Gens Ace 2s LiPo Battery 60C (7.4V/400mAh) w/JST-XH
Tattu 300mAh 2S 75C 7.6V Lipo Battery with JST-PHR Plug - Gens Ace
Gens Ace Adventure 5000mAh 2S1P 7.4V 100C HardCase Lipo Battery Pack W
Gens Ace 2S LiPo Battery 35C (7.4V/1100mAh) (Axial SCX24) w/JST-PHR – Limitless R/C
Gens ace G-Tech 35C 300mAh 2S1P 7.4V Airsoft Gun Lipo Battery with JST-SYP Plug - Gens Ace
Gens ace 2600mAh 6S 45C 22.2V Lipo Battery Pack with XT60 Plug
Gens ace G-Tech Soaring 2200mAh 7.4V 30C 2S1P Lipo Battery Pack with XT60 Plug - Gens Ace