Specification: 1Heavy duty 2with carbon steel ball bearing 3with a high load-bearing capacity 4more quietly than metal roller bearings 5low noise, stable performance and durable 6able to work in sub-zero temperatures and have low rolling resistance 7suitable for countless applications: sliding doors, windows and other furnitures Materialnylon, plastic color black, or per request sample free offered usage door and window processinjection wheel color red, orange, white, green MOQ 1000pieces delivery time15-25days paymentT/T, LC packingplastic bag inner, outside in carton