Corbeau has the option to add a 5^th slot, otherwise known as a submarine slot, to any of our reclining seats. The 5^thslot is installed in the base of the seat where you would run your submarine strap on a 5 or 6-point harness belt. Our fixed back racing seats are already equipped with this submarine slot but reclining seats are not. Having a 5^th slot installed eliminates having to run the submarine strap over the front of the seat and is recommended if using a 5 of 6-point harness belt.