1.Material of wheel is nylon, material of groove is iron with galvanized. 2.different color of wheel is available. 1.Material of wheel is nylon, material of groove is iron with galvanized or electroplating.2.different color of wheel is available.and we usually supply orange, green and white.3.usually used for door and window4.durable and anti-abrasive Our company specilizes in accessary for ...