Speed Dawg Black Pearl Skull Shift Knob High quality durable product made in the USA All graphics are subsurface and will not rub or wear off Polymer resin construction reduces the extremes of heat and cold that are associated with aluminum and steel shift knobs Solid brass threads and adapters. This item is packaged with a 3/8-16 brass master adapter and jam nut; 1/2-20 brass master adapter and jam nut; (additional threaded brass adapters are sold separately in a variety of standard and metric sizes) WARNING: Failure to follow the enclosed installation instructions could cause the shift knob to rattle or break. Do NOT overtighten or allow the shift knob to bottom out on the shifter. Always secure the shift knob with one of the enclosed jam nuts as directed by the enclosed installation instructions.