Chrysler is cascading its stop-start system in the NAFTA region to certain versions of the Jeep Cherokee and Chrysler 200 later this year, promising fuel-economy improvements of up to 3% (and a corresponding reduction in CO₂ emissions) over the conventional models. The technology made its NAFTA debut in the Ram 1500, for which it provides fuel-economy and CO₂ improvements of about 1%. System hardware includes a high-speed and "high-durability" starter (heavy-duty flywheel teeth and more robust solenoid) that cranks the engine faster upon restart, and a "beefier" battery (using absorbed glass mat technology) that powers air-conditioning and/or other features while the engine is off. When the brake pedal is released, control algorithms re-start the engine and engage the nine-speed automatic transmission within 0.3 s. A button allows the driver to turn the system off. The stop-start system will be standard on MY2015 Cherokees with the 3.2-L Pentastar V6 and MY2015 200s with the 2.4-L Tigershark I4.