... types Roller & Pulley For Conveying Systems (Diameter: 89mm, 114mm, 139mm etc):1. Application: . The idlers are playing an important part in ... seal style prevent the corrosion by impurity, water and air etc.; 3. Working life: 30,000 - 50,000 hours. 4. Conveyor ... idler Roller & Pulley for Conveying Systems (Diameter: 89mm, 114mm, 139mm etc)