Standard 3/8 inch x 24 threads , mounts and accessories . Works with antennas up to 60 inch long.Made from long lasting, top grade electro-polished stainless steel Note:The antenna spring is heavy duty, but it may be flex when the speed is too fast , or if it break down when the antenna being pushed or use it for some months ,importantly every person uses a different requirement,It may be springly,weak or stiff to you, but not the same to others.so please decide twice before you buy it. Improved Antenna Performance: The spring mount helps to reduce the impact of vibrations and shocks on the antenna, resulting in improved signal transmission and reception quality. Colour:As Shown Material:Stainless steel Due to different batches, there may be differences in product appearance and printed text, which not affect use Package Contents: 2 * Antenna Spring Mount Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.