This bike bottle holder mount bolt is made of aluminum alloy,it can last for a long time and is abrasion resistant. It is fit for most road cycling bike and mountain bike to use,it mushroom head,the apperance design is unique. It is designed for mounting the bike bottle holder to the bike frame,is a hex-head M5x10 type screw. There is a mini wrench,you can use it to install the screws or remove the screws for replacing. The screws are lightweight and small,is convenient to carry or store,the screws have smooth surface,convenient to clean. Specification: Material: Aluminum alloy. Color: Black,red,yellow,green,silver. Size: Show as picture. There might be a bit color distortions due to different computer resolutions. There might be a slight errors due to different hand measurement. 10 set of 2* Screw. (yellow )