Made of high-quality iron more durable and stronger Total Size:105x30mm/4.13"x1"(L*W) Package Content:2 x Black Speaker Mount Adapter with M20 Threading,8X Self-tapping screws Replaces existing 1 3/8" sockets M20 threading provides wobble-free connection between the subwoofer and compatible speaker poles Howonder provides a 12-month quality guarantee, if the product has quality problems, please contact us