The J Channel Vent is the luxury of a front flange
and the benefit of a back flange all rolled into one.
And, not to mention, the time saved from
not J-ing around the vent by hand.
The rear of the J channel is ideal for fasteners to connect the vent to the wall.
The standard J Channel is a 1" square pocket surrounding the face of the vent.
Don't forget to use rubberized window tape to seal the flange to the wall.
This is just added protection from gappage and leaks.
The depth of the channel can be specified in the comments box.
That is if the siding requires a wider receiver pocket.
The order form will ask where the J channel is to be located on the side.
This can be on the front (most common) or any depth away from the front.
If this seems too much,
the front flange is only the face flange.