Sheet Metal Supply Ltd.’s MegaLock 2 is a two-part perimeter edge flashing for single-ply, low-slope roofs. It includes a cleat and gravel stop. Radius System for curved perimeter edges. The perimeter edge system can be fabricated and curved to concave or convex radii. MegaLock 2 is available in 1/2-inch increments from 3-inch to 10-inch nail down sizes.