The M-Vac Extension Tubing is the length of tubing that connects the M-Vac collection device to the Support Equipment Case (SEC) durable machine that houses the vacuum pump and solution delivery system.  It comes in 5', 10', 15', 20' and 40'.  The most common length used in the lab or DNA collection room is the 5'.  If used in the crime scene a 15' or 20' tube is likely more appropriate.