Ribs of adjacent Lok Seam panels snap together, enclosing the concealed clips and provide a positive metal-to-metal lock. In turn, the enclosed clips positively secure the adjacent panels to the roof structure. Seams require no machine closing, yet are continuously and securely locked in place. By eliminating the need for mechanical seaming, installation time and cost can be greatly reduced. Also available in 1-1/2" rib height (US-150LS). The US-150LS has a slightly different locking detail from the US-175. (see below)