A high-quality pulley that is designed to be an idler in a belt system. Unlike a standard GT2 pulley, this one has no teeth and does not engage with the belt. Instead, it acts as a tensioner that keeps the belt tight and prevents it from slipping. It has a 5mm bore that fits on a stationary shaft or bolt, and a 6mm width that matches the width of a 6mm GT2 timing belt1. It is made of black aluminum, which is lightweight, durable, and resistant to corrosion. It also has two bearings that are pressed into the center bore, which allow the pulley to spin freely and reduce friction. It is suitable for 3D printers and other machinery that use GT2 timing belts for precise motion control.color black