The Sennheiser BA 2015 (article 009950) is a rechargeable NiMH battery pack for Sennheiser bodypack transmitters and receivers. It drops into the battery compartment in place of two standard AA cells and suits the evolution wireless G3 and G4 100, 300 and 500 Series bodypacks, the 2000 Series (SK 2000 / EK 2000), the Tourguide SK 2020-D and the EK 1039. The pack contains two 1.2 V NiMH cells rated at 1.5 Ah. Its integrated sensor lets the charging bay recognise it, reports battery status, monitors temperature while charging and prevents the charger from trying to recharge ordinary alkaline batteries, which protects both the charger and the bodypack. Using BA 2015 packs with a Sennheiser charging bay (such as the L 2015) or charging directly in a compatible bodypack lets theatres, churches, schools and rental companies stop buying disposable AA cells for every show while keeping predictable run times. The pack weighs about 60 g and comes with Sennheiser's two-year warranty. It is sold as a single battery pack; chargers are sold separately.