They are mostly applied in the construction of outsized informatory Signs that are mainly girderaged on piles or gantries.

The used screws Μ8Χ50, have properly shaped head, that  tenates the Signs to the piles with special hoops.

Each profile sheet is tenated to each pile with two screws.

This practice fascilitates the transport, and achieves quick and steady girderage on the piles (from one to three, depending on size) or the gantries.