We had to make sure that we kept all the tech and batteries warm, incase they stopped working under the harsh temperatures of near-space. Everything was placed inside a polystyrene dome to insulate everything inside, but we added a hand warmer and some bubble wrap to keep the temperature high inside.
1x Hand Warmer
This was placed in the middle of the polystyrene dome next to the GoPro and New Trent battery pack. It starts working as soon as you open the packet, and it reacts with the oxygen to create the warmth.
75p from local camping shop
Assortment of Bubble Wrap
The bubble wrap was bundled inside to insulate everything, and to make sure everything stayed in place inside the dome.