1/4 inch inner diameter, 3/8 inch outer diameter, plastic tubing made from the highest quality pure food grade silicone, perfect for any industrial, beverage, or home use you want. Pure silicone will last a very long time. Available in soft and squishy or harder and more transparent variants. Good for anything except high pressure. For you high pressure you should get 1/4 x 1/2 inch instead, which has a much thicker wall. Nexmetal silicone exceeds all NSF, FDA, and ANSI standards and is produced in cleanroom environment suitable for medical use. Tubing is individually packaged in sterile packaging. It is not sterilized, if you require this tubing to be sterile, the easiest method is to boil it in water.