Backrest
Do you require a hardback or softback backrest?
Soft Cushions
If you are mounting your cushion on a solid base that doesn't require additional support or foundation than a soft cushion (bow cushions, soft bench seats, backrest, coaming cushions, cushions with track, etc) is typically what is used due to the simple installation (4 snaps and screw studs typical, other mounting options available).
Hard Cushions
If you are wanting to screw into the back of the cushion for mounting (front console, leaning post,etc) or spanning an opening that requires support then you most likely need a hardback cushion. Our hardback cushions have a 1/2" kingboard foundation which provides great support and rigidity in addition to the foam tops.