Severne S1 - The S-1 is Severne's 4 batten maneuver oriented wave sail. Compared to the Blade, it has more backhand pressure for constant drive on the wave. The S-1 uses Severne light weight em3 x-ply material to ensure a great light weight overall feel while still retaining incredible durability. If you're a wave ripper that loves that loves a light weight and maneuverable sail, the S-1 is going to be your choice. The Severne Blade will still be a better choice for bump and jump conditions. The S-1 is a purebred wave sail.