The SR Suntour SP12 NCX Suspension Seat Post 350x31.6mm uses a proven parallelogram system for added comfort in the saddle. This suspension seatpost from SR Suntour moves down as well as back, providing a smoother overall ride.  SR Suntour SP12 NCX Suspension Seat Post 350x31.6mm Features Alloy arms. Brass bushing parallelogram system. Rider weight: 60-100Kg. Diameters: 27.2mm, 30.9mm or 31.6mm. Length: 350mm. Travel: 50mm  Colour: Black. Weight: 792g / 27.2mm.