Stainless Steel Pipe Note: Pipe sizes can be confusing as the actual size of the pipe has little or no resemblance to the actual size of the pipe. While tubes are identified by the actual Outside Diameter (OD) and Wall Thickness (W), pipe sizes are nominal and wall thickness is identified by what is known as a Schedule. Please refer to actual sizes of OD and Wall. Can't find the size you need? We can notified you by email when more inventory is added to this category? Click Here for Stainless Steel Pipe Inventory Email Updates