Solid colored  truck shifter knob. 2-1/8" diameter. Built-in 1/2-13 brass threaded insert. Made of ultra durable Partek resin. This  semi truck interior  accessory is made in the USA.  
Choose color from drop down menu.  

Matching Tractor/Trailer Air Valve Knobs, item 340686 sold separately.  

See more link for Installation Instructions.  
Installation requires shifter adaptor.  Choose 13/18 Speed, item 238690 or  9/10 Speed, item 238691, sold separately.  

• Turn your shifter knob into a steering wheel spinner with these adapters, item 366886