I have a Nissan Xterra and I designed a clip to hold my First Alert compact fire extinguisher. If you check my other items you'll find a wall clip for a Maglite. I use both to hold these out of the way beside the (factory) first aid bag mount.

This was made to be printed flat on the bed (so no supports needed). You might have to raft it. I printed 3 pairs and I had one that pulled up a little.
.30 resolution
Whatever temp you use. Can be ABS or PLA. I printed with black ABS.
Whatever speed you want....It took 80 mins at 90mm speed.