3-Size Precision Fit:​28.6/31.8/34.9mm​ sizes cover 95% bike frames! Matches seat tube ODs: ​28.6mm​ → Fits 27.8-28.8mm tubes (e.g. 25.4/27.2 posts),31.8mm​ → Fits 30.2-32.1mm tubes (e.g. 27.2/30.9 posts),​34.9mm​ → Fits 33.5-35.2mm tubes ( Measure frame tube OD before purchase!)Aircraft-Grade Durability:Forged from ​6061-T6 aluminum alloy​ with sandblasted anodizing – ​weighs only 40g​ (30% lighter than steel), resists rust & corrosion even in wet trails.1-Second Quick Release:Patented ​tool-free lever​ adjusts seat height instantly. Ergonomic knurled grip + ​safety lock​ prevents accidental slips during aggressive riding.Style Meets Function:​Glossy Black/Passion Red​ anodized finish won't fade. Hollow lever design saves weight while adding race-bike aesthetics.WOWSPORT 360° Guarantee:​12-month warranty​ Includes micro torque wrench for perfect 5Nm installation.