Looking to buy a SMALL battery, something that can replace this kind of battery

http://www.batterymart.com/images/products/mc/pc680.jpg

Voltage: 12 Volt
Capacity: 16 Ah
Type: Drycell
Length: 7"
Width: 3 1/16"
Height: 6 5/8"

Looking for local and immediate pickups, NY, CT, NJ, PA, MA, please PM me asap =]