These kits are used with the HGU-84/P Naval Aviator Helmet:

 

CEP508-K04, Kit includes Mini-CEP (CEP508-C15) and Interface (CEP900-I04) with a tube of Mixed Eartips (CEP002-EMXT)

 

CEP505-K04, Kit includes Mini-CEP (CEP505-C11) and Interface (CEP900-I04) with tube of Mixed Eartips (CEP002-EMXT)