The Comply™ TrueGrip™ Pro premium fittings are designed to fit certain truly wireless earphone models) and have a uniquely tapered design that precisely seals the ear canal to block out external sound for better sound and call clarity, in addition, the TrueGrip™ Pro fittings have a shorter design to ensure a perfect fit in the charging socket. The Pro design features a WaxGuard coating to protect against external contaminants.