It is made of high quality material, which is very durable and reliable. The strong compression plug is good for the carbon tube, it provides more pressure and also protects the carbon tube. Eliminates the risk of damage and provides extra support for the fragile top edge of the steering. (Star nut is for aluminum tubes only). WIDE APPLICATION: The stem Extender which is very practical and useful for use, perfect for mountain bicycle, road bike, , the handlebar fork stem(Please note: This product is not suitable for extreme sports use.) Easy to install. There is no need to use or force to knock in, as long as the hex wrench is screwed in. Replaces the conventional star nut .When you finish mounting, the stem riser is invisible outside, which keeps your bike more beautiful. Colour:black Material:aluminum alloy Size:30MM Package Contents: 1 x Fork Stem Extender 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.