Specification : Product name: Gear Knob Material: Aluminum Length: 73.5mm/2.89in Inner diameter : 18.6mm/0.73in Thread adaptor diameter : 8mm / 10mm /12mm Fitment : Universal fit for most manual transmission vehicles Features : 1.Made of Aluminum for enhancing strength, durability and shifting speed. 2.Weighted aluminum construction for improving shifting efficiency by increasing inertial force. 3.Enhance shifting more smoothly and quickly while shifter is engaging into the gear box. 4.Come with with 3 adaptors8MM, 10MM, 12MM make it fit most vehicle. 5.For both manual or automatic transmission. 6.Direct replacement, no modication required. Installation Steps : 1.Remove the original car gear shift knob. 2.Take Plastic adapters suitable size For shift knob. 3.Put The gear head into the shift knob. 4.The gear head directly set into the shift knob rod. Note: 1.We provide clear pictures, measurements where possible. Please check as much as possible to make sure the item is the one that you need. 2.All dimensions are measured by hand, Please allow 0.5-1 inch difference due to manual measurement.1inch2.54cm. 3.Professional installation is highly recommended .If you want to know how to use or use it,please contact us by Email Package List: 1 x Gear Knob 3 x Adaptor 8mm 10mm 12mm