This METRIC shift knob adapter kit contains 3 different sized adapters and the 3 corresponding jam nuts for use with shift knobs that have a 16mm x 1.50 I.D. thread size. The kit includes 1 each: 12 mm x 1.75 adapter & jam nut, 12 mm x 1.25 adapter & jam nut, 10 mm x 1.50 adapter & jam nut. Adapters are comprised of solid brass. California residents click here for Proposition 65 WARNING label. Made in the USA.