Since the PCI slider and adjustable seat mounts do NOT come with hardware to attach the seat to the side mounts, you will need the Side Mount to Seat Hardware Kit. Safety is always my number one concern when racing. I use this same kit in all my race cars because it is the highest quality hardware available. Not only are the components strong (the bolts have a tensile strength of 150,000 psi and hardness of Rockwell C32), but also are corrosion resistant. The seat hardware kit includes quantity 4, JIS spec, high-strength steel, Class 10.9, zinc-plated, flanged hex head, 25mm long, M8 bolts and quantity 4 over-sized, 304 stainless steel M8 washers.