BA 151 : Batterie Rechargeable (Accumulateur) Sennheiser (casque TV)
MPF Products BA 150, BA 151, BA 152 Rechargeable Battery Replacement Compatible with Sennheiser IR and RF Wireless Headsets (Compatible Models Listed in Description Below)
2-Pack Battery for Sennheiser HD IS RI RR RS Set Series Headphones, BA150 BA151 | eBay