Momentum PakYak Auxiliary Battery Holder Description: The Momentum PakYak Auxiliary Battery Holder works to harness the power of PakYak Auxiliary Batteries for an expansion of ride range. Stored inside the storage case included on the PakRak, this additional battery adds the benefit of extended ride time without messy or complicated install onboard PakYak+ E-Bikes. Features: Battery holder for PakYak Auxiliary Batteries