What tubing do I require for my Hei-VAP rotary evaporator? We recommend: 591-35000-00MPE: Tube Set for Hei-VAP 12m This contains 12 m of tubing suitable for connecting your Hei-Vap to both a vacuum pump as well as to a water source or recirculating chiller. The tubing is transparent, FDA-approved and UV-resistant. If you would like to supply your own tubing, the specification for both the water and vacuum connections on a Hei-Vap is 8 mm internal diameter.