These shocks are high grade products sourced from BikeIt using worlds leading brands such as YSS. Motorcycle shocks nearly always use a coil-over spring, In other words, the spring for the rear suspension is a coil spring that is installed over, or around, the shock. In terms of adjustment, rear shocks span the range from pre-load adjustments only to racing shocks with adjustments for pre-load and four different kinds of damping. Most shocks have internal oil reservoirs but some have external ones and some offer air-assisted damping. Twin-shock or twin shocks refers to motorcycles that have two shock absorbers