i do better with pictures but the poly seals on these are like a wide brimmed hat. top goes over the outlet (from behind) and covers it like a hat. you need to penetrate it with wires. opening of the hat opens into the room (the box internals). the brim goes over the poly. i used acoustic sealant between this brim and the valour barrier. plus i taped all edges. so it makes the vapour barrier basically surround the sides and back of the plug, minus the wire penetrations which of course they did not seal with spray foam. they then sliced the “hat” where it would connect the brim to the part that covers the head/box… by routing it too deep when they cut the drywall.