The Power Part…
PowerPlay’s Power section is a pair of two 18500, Li-ion cells, that can power a Dominator HDO + rapidFIRE + DVR for up to 3 hours *.
To recharge, either use the built-in USB-C port for up to 1.5A charging, or simply pop out the cells, and replace with a freshly charged set.
The PowerPlay ships with 1400mAh cells, but larger capacity 2040mAh cells are available from most vape shops, and are the same ones used in the FrSky X-Lite radios, so any decent FPV retailer will stock them.
* 3 hours with 2040mAh cells, not shipped with the product

Head Strap
The PowerPlay ships with a head-mounting accessory pack. A quick-release clip mounts on the rear of the standard goggle headstrap, and the new included top-strap ensures a comfortable fit.
A short ‘Y’ cable connects power, A/V, and the fan connector.
The rear-mounted DVR has the advantage of letting people standing behind you see what you, the pilot, is seeing.
A longer version of the cable is also supplied, for those who would rather keep their battery/DVR in a pocket, and keep weight off of the head.

Other usefull information

The ImmersionRC PowerPlay is a new product combining a best-in-class DVR, with a goggle battery. 
The DVR supports h264 encoding, high bit rates, and frame rates of up to 60fps for fluid capture of race, freestyle, and whoop footage. 

Shipped with all hardware for two ways to use, head mounted, or pocket mounted. 

Uses standard 18500 Liion cells, as used by the popular FrSky X-Lite series of R/C remotes. 

• Power: 2x 18500 Li-ion cells (without protection circuits)
• Batteries: 2x 18500 1400mAh included. Up to 2040mAh cells supported for longer battery life.
• Power Switch: Yes... powers both the DVR, and the Goggles
• Video File Format: h264
• Video File Resolution: 720x576 (PAL), 720x480 (NTSC)
• Video Data Rate: ~15Mbps (PAL), ~8Mbps (NTSC)
• Black Flashy': None