I like to design parts that work straight off the printer bed. This part is no exception.
It needed to stop wires running into the engine bay from contacting and wearing against the metal surfaces found in the engine bay. It also needed to use simple easy to obtain rubber extrusions as I wanted to keep the costs to a minimum. I like the way that rubber and plastic glands are able to hold the wires in place with their screw and rubber fitting I wanted to be able to have the same thing in my grommet. I designed it so that one cable tie could be used to hold all the cables and rubber fittings in place, once they had been run through the grommet (no need for screw fitting to be integrated into this design when I can use a cable tie). I also wanted more than one wire, hose or cable to be able to go through this hole as it was quite large (a waste of space for only one cable) and glands only allow one of these to go through each hole and I didn't want to cut any more holes through the fire wall.