The Sennheiser 578881 is a pair of replacement black ear cushions for various sennheiser headphones:
Ear cushion (1 pair), suitable for: HD 25-1, HD 25-1-II, HD 25-13, HD 25-13-II, HD 25-II, HD 25-BA, HD 25-C-II, HD 25-IFE, HD 25-SP, HD 25-SP1, HD 25-SP-II, HMD 25-GK, HMD 25-XQ, HME 25-1, HME 25-KA, HME 25-KA-2, HME 21-TELCOM, HMEC 25-6A, HMEC 25-8A, HMEC 25-8A-1, HMEC 25-BA, HMDC 25-BAA, HMEC 25-CA, HMEC 25-CAL, HMEC 25-CAP, HMEC 25-CAP-Diamond, HMEC 25-DAP, HMEC 25-KA, HMEC 25-KAL, HMEC 25-KAP, HMEC 25-KAP-2, HMEC 25-KAP-2 Diamond, HMEC 25-KAP-1, HMEC 25-KAV, HMEC 25-KAX-1, HMEC 25-KAX.