causes the gusset panels 36 to activate about the fold 35 and the reverse 45 u00b0 fold 37 the base end panel 27 is then glued to the side end panels 38 the top 12 can then be folded down and glued to the side end panels generally not in the region of or blocking the push through flaps 30 40 once folded the free edges 45 of the gusset panels 36 are elevated from the base 18 of the carton this forms a tray like base area such that after the lines of weakening 24 are opened ice or other substance can be deposited in the carton 10 around the bottles the paperboard can be treated with a water resistant coating such as u201c aquakote u201d trade mark as the ice melts some cold water is retained in the carton up to the level of the free edges 45 of the gusset panels 36 thus resisting leakage for a period of time in this way the pack can be used to chill or keep chilled the contents of the carton and can still be moved due to the wet strength of the treated paperboard this is in contrast to corrugated board which has a much lower wet strength the tray aspect of the base is also advantageous when a number of cartons are on pallets ready for distribution with corrugated cartons a broken bottle can through leakage adversely affect a whole pallet which.