Have this mounted behind the headrest
Lightning X Products Vehicle Head Rest IFAK Trauma Bag w/ Laser Cut MOLLE, Detachable Quick Release Pouch - TAN
https://www.amazon.com/dp/B091D664BP/ref=cm_sw_r_apan_glt_fabc_Z2J0PFV9YSZSTZY1RJ0R
Filled on the trauma side it's with a 2nd cat tq inside along with a NAR MFAK refill kit plus added burntec burn pads extra guaze and chest seals and trauma sheers.
On the other side of the bag is basic first aid boo boo stuff I'm around a lot of long distance hikers on the AZ Trail so some blister stuff and KT tape.
Solid bag attaches via velcro so can rip off and go.
Had to grab it once when we heard a car crash below our camp site turns out was a single vehicle roll over.