5-Size Precision Fit:Choose exact diameters: 25.4, 27.2, 28.6, 30.9, or 31.6mm – instantly compatible with 99% mountain bikes, road bikes, BMX, and commuter bicycles. Always measure your current seatpost first!Aircraft-Grade Aluminum:CNC-machined from 6061-T6 aluminum alloy: 30% lighter than steel, ​corrosion-resistant, and supports ​max 265kg (580lbs)​​ weight. Ideal for rugged MTB trails & daily commuting.Tool-Free Angle Adjustable:Patented clamp head design allows ​15° tilt adjustment in seconds​ – dial in your perfect saddle position without wrenches. Includes anti-slip grooves for secure grip.Safety First Design:Laser-etched ​MIN INSERT line​ warns against over-extension. ISO 4210 safety certified. Installation tip: Insert at least 3.2" (8cm) below frame top tube.US-Based Support:Backed by WOWSPORT's 24-month warranty + 24hr customer service. Package includes installation hexagon wrench