The biggest Coolster ATV is Coolster ATV-3150DX-2. It is a 150cc Fully Automatic Full-Sized Utility ATV. This ATV-3150DX-2 by Coolster is the longest-running utility ATV, so it deserves a special mention. With its compulsory powered, 4-stroke 150cc engine and large 23"/22" tires, it boasts outstanding durability.