Web: www grandmfgcn com E-mail: grandmfgcn at yahoo com Oil level Sight glasses, sight gauge, sight gage, oil level indicator, liquid sight glass, sight window, view ports, male thread sight glassesMaterial Body: Aluminum, Steel and Brass O-Ring: Viton and NBR Glass: Real Glass Glass Thickness: 2mm to 5 mm Glass Type: General Glass, Tempered Glass and Borosilicate Glass Resist Temperature Range: - ...