Optima Yellow Top Yt U - 4.2 55 AMP Apologies for the confusion in my previous response. The Optima Yellow Top YT U-4.2 with a 55AMP rating, is a specific model of car battery manufactured by Optima Batteries. Here's a description of the product: Type: The Optima Yellow Top YT U-4.2 is a dual-purpose battery designed for both starting and deep cycling applications. It is built to provide high cranking power for starting vehicles and can handle repeated deep discharge and recharge cycles. Technology: This battery features Optima's SpiralCell design, which consists of tightly wound pure lead plates. The SpiralCell design provides a strong and clean power source, ensuring efficient energy delivery and improved resistance to vibration and impact. Voltage and Capacity: The Optima Yellow Top YT U-4.2 operates at 12 volts, which is the standard voltage for most automotive systems. It has a capacity of 55 ampere-hours (Ah), indicating the amount of energy it can deliver over a certain period. Application: This battery is suitable for a wide range of applications, including cars, trucks, SUVs, boats, and other recreational vehicles. It is particularly useful in vehicles with high electrical loads or those that require extra power for accessories, audio systems, or other demanding electrical components. Performance: The Optima Yellow Top YT U-4.2 provides reliable starting power, even in challenging weather conditions. It is capable of delivering a strong burst of energy to start the engine quickly. The battery's deep cycling capabilities allow it to handle multiple deep discharges and recharges without losing performance, making it suitable for off-road vehicles and applications that require sustained power delivery. Benefits: Deep cycling and cranking power all packed into one battery. Lasts up to 3 times longer than traditional flat-plate batteries. Constant performance quality, which keeps your battery running at the same level even as it's being discharged. More power in the initial 1, 3, 5 and 10 seconds of the starting process than comparably rated conventional lead-acid batteries. Ideal for seasonal use, fully charged it can sit unused for up to 12 months at room temperature (or below) and still start a vehicle. 15 times more resistant to vibration than traditional lead-acid batteries. Mountable in almost any position Specifications Model Number: YT U 4.2 Voltage (V): 12 Cold Cranking Amps @ -18°C (A): 765 Cranking Amps @ 0°C (A): 870 Reserve Capacity (Minutes): 120 Capacity (C/20 Rate) (Ah): 55 Internal Resistance (ohms): 0.0028 Type Post/Terminal: Dual SAE & GM BCI Group: D34/78 Minimum Weight: 19.9 kg Length (mm): 254 mm Width (mm): 175 mm Height (mm): 200 mm