1-1/2 Inch Copper Pipe - Type M. The tubing measures 1-1/2 Inches nominal size with an outside diameter of a 1-5/8 inches. It is shipped in 5' lengths which makes it great for smaller applications that require a shorter distance of tubing. It is important to note that this tubing will use 1-1/2 inch fittings such as, Copper (soldering required in most cases), Flare, Crimped/Pressed (power crimper necessary) or Compression connection fittings. This particular copper tubing is type M, which has a thinner wall than the common type K. Type M copper tubing is great for water supply lines in both commercial and residential properties. Copper tubing applications may include a refrigerant line in your Heating, Cooling and Air Conditioning (HVAC) System or as supply lines for hot and cold tap water. However it should never be buried as its wall thickness is not strong enough for that amount of pressure. NOTE: Due to shipping regulations five foot sections is the maximum length shipped in straight pipe. If Longer lengths are required coiled pipe is another available option .