Because so many of these parts are used in a project's early development, ThermoPore has developed a series of sizes that accommodate a simple interference fit with standard Tygon® medical grade tubing. Information from Saint-Gobain's regarding their line of Tygon® tubing is available by clicking on the following link, Tygon®, and their pdf product data sheet can be viewed by clicking Tygon® pdf. Tubing inside diameters are listed for interference fits between the outside diameter of the porous plastic part and the inside diameter of the Tygon® tubing. Tubing outside diameters are listed for interference fits between the inside diameter of the porous plastic part and the outside diameter of the Tygon® tubing.