1. Parallel idler: used to support an unloaded conveyor belt and maintain its smooth operation. Common specifications include a diameter of 108mm and lengths covering various sizes such as 190mm, 200mm, 240mm, 250mm, 305mm, etc; Parallel rollers with a diameter of 133mm are usually 305mm, 375mm, 380mm, 455mm in length, etc; Parallel rollers with a diameter of 159mm, lengths such as 375mm, 380mm, 455mm, 465mm, etc.

2. Groove shaped idler: It is generally a three roll structure that can form a groove shaped cross-section, used to carry materials and increase conveying capacity. The groove angle is commonly 30 ° or 45 °. For example, for an 800mm belt conveyor, a groove shaped roller set with a middle roller length of about 950mm may be used.

3. Self aligning idler: There are universal, friction reversible, strong type, cone type, spiral type, combination type, etc., which are used to prevent the conveyor belt from deviating. There will be DTII type for tapered centering rollers, with specifications such as B=1400, φ 133x655, etc.

4. Buffer roller: mainly used to reduce the impact of material falling on the conveyor belt, often installed below the material dropping point. The buffer rollers used in trough belt conveyors have specifications such as Φ 159.