Bike type:Mountain Bike Size:30.9mm Material type:Aluminium Batteries included?:No Package Dimensions:38.9 x 8.9 x 5.1 cm; 490 Grams welcome to my store , Hope you have a pleasant shopping trip! Features: 1.Forging process exquisite workmanship and lightweight installation is simple and convenient. Installation method: loosen the old seat, remove the seat tube, and then fix the seat on the new seat tube with bolts2.Choose the appropriate size: Method 1. Take out the original seat tube to view the specifications and select the same size seat tube; Method 2. Measure the inner diameter of the frame vertical tube and select the appropriate seat tube diameter;SpecificationsColour: BlackMaterial: 6061 T6 high-strength aluminum alloySpecifications: 27.2mm/30.9mm/31.6mm*350mm Suspension stroke: 45mmCompatible with 5mm steel rail and 7mm carbon railPackage List:1X Suspension Seatpost Notes: 1. Due to the difference between different monitors, the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the pictures.2. Please allow 1-2cm slight dimension difference due to different manual measurement. About this item The Outer Tube Is Made of T6 High-strength Aviation Aluminum Alloy, Which Is Strong and Durable; Choose the Appropriate Size: Method 1. Take Out the Original Seat Tube to View the Specifications and Select the same Size Seat Tube; Method 2. Measure the Inner Diameter of the Frame Vertical Tube and Select the Appropriate Seat Tube Diameter; High Quality: The Inner Tube Is Buffering, Shock Absorption, Abrasion Resistance, Impact Resistance, High Temperature Resistance, Acid and Alkali Oil Resistance, Etc., the Compressibility Is About 50%, the Recovery Elasticity Is Strong, and It Is Permanently Non-deformable, Etc. The Screw in the Bottom End of the Seat Tube Can Adjust the Softness and Hardness of the Seat Tube to Get the Best Riding Experience. The Softer the Adjustment in The-direction, the Harder the Adjustment in the + Direction. The Seat Tube Suspension Stroke Is 45mm; SHOP WITH CONFIDENCE: To Provide You With the Highest Quality Service, If You Have Any Question, Please Feel Free to Contact Us.We Will Provide After-sales Service Until You Are Satisfied. The Outer Tube Is Made of T6 High-strength Aviation Aluminum Alloy, Which Is Strong and Durable; Choose the Appropriate Size: Method 1. Take Out the Original Seat Tube to View the Specifications and Select the same Size Seat Tube; Method 2. Measure the Inner Diameter of the Frame Vertical Tube and Select the Appropriate Seat Tube Diameter; High Quality: The Inner Tube Is Buffering, Shock Absorption, Abrasion Resistance, Impact Resistance, High Temperature Resistance, Acid and Alkali Oil Resistance, Etc., the Compressibility Is About 50%, the Recovery Elasticity Is Strong, and It Is Permanently Non-deformable, Etc. The Screw in the Bottom End of the Seat Tube Can Adjust the Softness and Hardness of the Seat Tube to Get the Best Riding Experience. The Softer the Adjustment in The-direction, the Harder the Adjustment in the + Direction. The Seat Tube Suspension Stroke Is 45mm; SHOP WITH CONFIDENCE: To Provide You With the Highest Quality Service, If You Have Any Question, Please Feel Free to Contact Us.We Will Provide After-sales Service Until You Are Satisfied.