MFSL Mobile Fidelity Original Master Sleeves - Protective Inner Sleeves for LP phonograph records. Imitation is the highest form of flattery, but don't be fooled! Only the Original Master Sleeves from Mobile Fidelity Sound Labs offer the finest protection for your valuable records. These imported, three-ply, anti-static, 12" premium record sleeves have been used in MFSL LP packaging for decades and now you can use them to care for all your vinyl! The best record sleeve available!