The blister contains 3 pairs of foam ear. No foam replacing the temporal support pads of the helmet PORTAPRO (yes they wear out much less). The diameter is 48 mm. Well suited for headphone Koss PORTAPRO. Compatible headsets are indicated on the blister: KSC7; KSC11 / KSC12; KSC17; PTX6 / CX6; KSC75 Titanium; KTXPro 1; KTX8 / KTX16; Porta Pro; Porta Pro 2; Sporta Pro; UR5.