Slim, black and made for ROVE carts. This ROVE battery has a 350mAh cell and works with all ROVE cartridges. Three power settings let you fine-tune the output, whether you like a lighter draw or something fuller. It's fully rechargeable with the charging cable, so it's ready again when you are. Now and then, wipe the connection with a cotton swab dipped in isopropyl alcohol to keep residue from building up. ROVE cartridges are sold separately.