There are two filters built in to the LTV, both on the left side. One for the intake and one for the fan.
The breath outlet port is the 22mm connector where the circuit hooks into the vent. We had a filter between the circuit and vent. I guess that is the one they are referring to.
Jenna - Adoptive Mom of Dovid (traumatic brain injury, vent dependent) 12/09/2005 - 03/28/2011 and Foster Mom of Lil P (ASDx2, VSD, pulmonary stenosis, RTA, FTT).