A swingarm, or "swinging arm" (UK), originally known as a swing fork or pivoted fork, is a single or double sided mechanical device which attaches the rear wheel of a motorcycle to its body, allowing it to pivot vertically. The main component of the rear suspension of most modern motorbikes and ATVs, it holds the rear axle firmly, while pivoting to absorb bumps and suspension loads induced by the rider, acceleration, and braking. A gear case, also known as a chain case or chainguard, is an enclosure for the bicycle chain and sprocket assemblages commonly employed by utility bicycles. It serves to protect the cyclist from being soiled or trapped in the chain rings and tends to fully enclose the drive train.