The Bosch GAX1218V-30 Dual-Bay Charger can charge Bosch 18V, Bosch 12V Max and mobile phone batteries through the 2.1 amp USB port. This one charger provides the ultimate convenience to users who need to charge both Bosch 12V Max batteries and Bosch 18V batteries. It also provides a 2.1 amp max USB port to power up a cell phone (and other devices). It quickly charges batteries and it provides LED indicators so users can monitor the charging while they work. It charges a spent Bosch 18V 4.0 Ah battery in 85 minutes and a spent Bosch 12V Max 2.0 Ah battery in 45 minutes.