The Shark Slider S1 is a modular slider supporting up to 15 lb loads (11 lb with extension rails) and offering smooth movement thanks to silent bearings, synchronous belts, and a flywheel that adds inertia. The flywheel adds a damping effect to your slides, ensuring smooth acceleration/deceleration as opposed to jerky starts and stops. It achieves this through its centrifugal force while the slider belt is connected to it.