HY6 - fits Pro mag, Pro Tac mag, Pro slim, Pro Tac slim, ultra 28, ultra 33 and ultra Pro models contains (2) Pro form leather sealing rings, (2) microphone covers and (2) sets of interior foam for battery covers. Easy to use 'peel & stick' backing. Special soft foam provides the ultimate in comfort and sound deadening qualities. Conforms for a complete fit for glasses wear. Replacement recommended every 9 to 15 months.