Gel Cups typically squish and lose a good seal when compressed for a long time, this will prevent that while in storage.

Might work for other brands, leave a comment if it does!

should fit all these models plus Peltors comtacs

WorkTunes Connect (90543), WorkTunes(TM) Connect + Gel Cushions (90544), Peltor Sport Shotgunner II (97040), Bull’s Eye (97041), Ultimate (97042), Tactical 300 (TAC300), Tactical 500 (TAC500), 3M Pro-Grade (90565), 3M Pro-Grade Hi-Viz (90566)