Here's what other sites are saying:
Instead of 4 individual hangers suspending the seat, the truss is a one piece unit that provides increased stiffness, strength, and efficiency. 4"" Ash trusses are sold in pairs. They can be cut to fit specific applications and can be stained to match existing trim. One truss kit and 1 truss hardware kit is all that is needed to mount 1 canoe seat.
Mad River Seat Truss Hardware Kit
Cascade Creek Yakgrips
$13 - $14
L.L.Bean Sit Backer Canoe Seat
WindPaddle Cruiser Sail
$126 - $175
NRS C-7 Leafield Valve Adapter
Jackson Kayaks Rudder Kit For Cuda
Surf to Summit Coiled Paddle Leash - Touring 8'
Jackson Kayaks Rudder Kit For Big Rig