All tool wrap is labeled 20 inch for listing purposes. The tool wrap comes from the mill 19.5 inch (+/- 0.5 inch) wide. The thickness is 0.002" and the length is your choice of 10ft, 25ft, 50ft or 100ft long. If you need something other than these 4 lengths, please contact us through our Amazon store. #309 is rated for (2250F Max Temp) #321 is rated for (2000F Max Temp)