This FX Carbon Fiber Barrel Sleeve is specially developed to stiffen up the liner of your FX air PCP, strongly reducing the harmonic vibrations (oscillating movement). By doing this, the barrel will have less movement, making for a better accuracy.
Carbon fibre is used, as this material adds incredible stiffness while barely adding any weight. The tolerances are extremely tight, making the use of glue superfluous when mounting the FX Carbon Fiber Barrel Sleeve.