12V Optima Blue Top G27 Start/Deep Cycle Battery - 66Ah

Optima BLUETOP® Marine Batteries –
The light gray case BLUETOP dual-purpose battery can be used for both starting and deep cycling; it is a true deep-cycle battery with extremely high cranking power.
The dark gray case BLUETOP starting battery should be used when a dedicated starting battery is required; it should never be used for cycling duty.

Optima Bluetop Batteries are high performance AGM (Absorbent Glass Mat) batteries with exceptional runtime and more recharges than you would get from a traditional lead-acid battery.
They feature both automotive (SAE) and threaded posts, outstanding resistance to vibration, with high efficieny power generation and faster recharge times.
Versatile BlueTop Marine and RV batteries are ideal for those who need a power source that requires no maintenance, and provides a safe start with plenty of power to run accessories.

Key benefits of Optima Bluetop batteries include high starting power (both starting and dual use versions), up to three times more recharges than any other marine battery (dual use models), 15 times more resistant to vibration, leak proofness, and they can be mounted in virtually any position without maintenance.

BlueTop batteries feature both SAE automotive posts for starting applications, and 5/16" threaded studs for easy installation in your boat or RV. The light gray/dual use models should be used in boats and RVs. They are ideal for powering heavy electrical loads including trolling motors, GPS, pumps, fish finders, winches, etc. They are also ideal for trucks with winches, cars with high-demand audio systems, commercial vehicles, etc.

• High power density and exceptional running time between charges
• Higher, more consistent voltage under large loads
• Spiral design provides lower internal resistance for faster recharging and consistent power output
• Longer service life – up to 3 times the cycle life of a traditional battery
• More economical than ordinary batteries over the long life of the battery
• 95% charge efficiency; 80% depth of discharge capability (compared to 50% for lead-acid)
• Can be used with high output alternators
• Spill proof - no excess liquid; can be operated in any position without the risk of leakage
• Never needs water; sealed - so no corrosion can form on the posts, connectors, or cables
• Unaffected by vibrations that destroy ordinary batteries
• Dual top posts: SAE automotive and 5/16"-18 UNC stainless steel threaded studs for lug-style battery cables
• Overall dimensions (including terminals): 12-1/4"L x 6-7/8"W x 9-7/8"H
• 2 year free replacement warranty

Sorting out Optima Batteries –
All dark gray Optima batteries (regardless of the top color) are starting batteries,
and all light gray Optima batteries are starting/deep-cycle (dual purpose) batteries.
Also Note: The difference between BLUETOP and YELLOWTOP dual-purpose batteries is that BLUETOP batteries have both automotive (SAE) post and threaded stud terminals, while YELLOWTOPS (other than D31T) only have SAE post terminals.