Delivery complete with groove nails. Colored hooks are hot-dip galvanized and powder-coated. To be installed centrally on the rafters. A minimum of two hooks is required for the first ladder, and at least one hook for each additional ladder. In accordance with the Construction Products Regulation 305/2011 (EU) and DIN EN 517. Safety roof hooks according to DIN EN 517 must be installed on roofs with a pitch of 22.5° to 75°. They should be distributed on the roof surface as follows: the upper row less than 1.0 m below the ridge, intermediate rows at less than 5.0 m distance from the row above, and the lower row less than 1.5 m above the eaves, each measured in the roof pitch. The horizontal distance between safety hooks in a row must not exceed 2.0 m. To be used at eave heights over 3.0 m.