Remember, slip couplings require TWO shrink sleeves to seal..

Shrink Sleeves for light Wall Systems 

A heat shrinkable polyolefin band that shrinks when heated with a heat gun and wraps around the connection.  The resulting joint is mechanically strong and is vacuum tight!  A great product. Recommended for use in systems under 15 psi.

NOTE:  Based on our experience. Shrink sleeves are the least expensive method of joining light wall tubing. Use shrink sleeves with expanded end fittings for 4"Ø and less, and compression couplings with straight ends on larger sizes.