SL-B26® protected Li-Ion rechargeable battery pack with built in micro-USB charge port Charges in 5 hours Integrated safety circuit protects battery pack from overcharge/overdischarge 2.75 in (7.0 cm); 1.7 oz (48g) Use the SL-B26 USB battery to power the PolyTac® X USB, PolyTac 90® X USB, ProTac® 90 X USB, ProTac® 2L-X USB, ProTac® HL-X USB, ProTac HL® 5-X USB, Siege® X USB, Stinger® 2020, Survivor® X USB, Vantage® 180 X USB, and more to transform these multi-fuel lighting tools into rechargeable systems