This is the Large LiPo Safety Sack from Venom.

FEATURES:
Constructed of flame resistant material, this sack is used by R/C pilots and racers to contain possible explosions from LiPo batteries involved in a crash or during charging or discharging 
Assembled with high temperature fireproof thread 
Closure flap snaps shut to better contain fire and debris in case of catastrophic failure
Fits into any field box or pit box

INCLUDES:
One large LiPo Safety Sack

REQUIRES:
Placing battery to be charged toward bottom of bag, routing charge leads through vent at top seam and snapping flap closed