Product name:Bicycle Hydraulic Disc Brake Caliper Insert Product size about : 30.7mm*5.5mm/1.21in*0.22in Specification:M4*30 Product color: As shown in the figure Product material:Aluminium CT4/Gr5(Bolts)+Carbon Steel (Circlip) product features: 1.Material: This screw is made of TC4 titanium alloy, which has good mechanical properties, toughness and corrosion resistance. 2.Thread size: Bicycle oil disc titanium screws usually use M4 thread size, M4 means the thread diameter is 4mm. 3.PDV Coating: The screws are also coated with PDV (Physical Vapor Deposition) coating technology for for surface, the colour is beautiful and not easy to fade away.PDV coating can increase the hardness, abrasion and corrosion resistance of the screws, and improve their service life. Precautions: 1. As we all know , the different computers display colors differently, the color of the actual item may vary slightly from the following images. 2. If you feel difficult to choose the size, you can contact us at any time. We will give you some suggestions, but for your reference only. Shipment includes: 1 pc Bicycle Hydraulic Disc Brake Caliper Insert