This is a battery box (not to replace a LiPO safety bag, or any other LiPO safety boxes) to protect the LiPO battery from outside hardships. I use mine in a soft pouch attached to my Airsoft rifles stock - as such this cover only acts to protect the battery from getting pierced or damaged due to the soft pouch.
The dimensions are internal:
110mm (roughly) x 34mm x 18mm with a 3mm thick wall all round
I have also left a gap, on the lid side, for the battery wires.
The battery is a 2200mAh 7.4V
Printed with ABS with no supports. I turned the box on its side to make the bridge distance smaller.
Printed using a Prusa i3