Global Roofing Solutions Klip-Lok 406 roofing roll-formed in continuous lengths. Klip-Lok 406 sheets should be suitably supported clear of the ground. The profile is roll-formed from certified steel. The profile shall have 3 trapezoidal ribs at 203mm centres giving a nett cover of 406mm. The male rib shall have spurs to ensure a positive double interlocking action at side-laps. Each pan shall incorporate two stiffener ribs.