The Optima½ Troll Fury (Model TF1800) combines two D34M marine batteries in a rugged ABS polymer outer case which can be secured to the deck with bolts through its four corners. We include cables allowing you to choose either 12v parallel or 24v series configuration. Designed for the rigorous demands of professional and sport fishermen, the Optima Troll Fury Blue Top battery offers long reserve time, (see specs below) physical durability and a fast recharge rate. Batteries can be used with or without outer case. Click to see Optima Troll Fury trolling motor battery with case open. Outer case dimensions are 8.5"W x 8.4"H x 23.25"L. Amp hours: 55@24V or 110@12V. CCA: 750@24V or 1500@12V. Reserve minutes: 120@24V or 240@12V. See more specs in on the D34M batteries in the deep cycle table above. (Note: Optima D31M, D31A and D31T batteries will NOT fit inside a Troll Fury case... the Troll Fury case will only hold 34-series batteries.The OPTIMA½ is like no other battery found in today's market. OPTIMA's unique Spiralcell design offers the greatest technology in providing a strong and clean power source that far surpasses any of today's filled lead/acid batteries. With OPTIMA under your hood, you can count on a longer lasting battery life under starting and deep cycle applications. Today's power demand from cars, trucks, and SUVs are greater than ever. Over the course of the century we have upgraded and customized our vehicles in such a way never imagined by early engineers. There continue to be more lights, LCD screens, gaming systems, stereos, laptops, and cell phones going into cars, all demanding a greater power source. OPTIMA can provide all the power needed to run these power pulling vehicles. OPTIMA batteries always has safety in mind, with its spill-proof case it helps to ensure the safety of the environment, your family and you. Powerful, 2x longer-life, safety, spill-proof, vibration resistance, multi-position installation whether you're working, driving cross country or for just play, let OPTIMA help you maintain the power demands you require.