Choosing Rollers: Smaller 38 mm rollers are more economical and the conveyor will retract to an overall smaller size. 48 mm rollers tend to last longer than the smaller rollers due to their radius, bearing, and turn speed Heights: All models have adjustable heights with additional heights available upon request Capacities: 50 kg per meter on a level surface Ideally suited for truck loading and unloading, distribution centers, packaging, portable assembly lines, shipping and receiving Carton Boxes. Continuous Duty Multiple Drive Motors - Line speed adjustable from 0 to 20 mtr per minute. Durable DC drive motors with 220 VAC.