The triple fins, in thicknesses 2-3-4 mm is designed to be able to train joints of various widths, removing, if necessary, the unused fins. To realize 4 mm joints the support is ready for installation; for 3 mm joints just remove the 4 mm fins; for 2 mm joints remove the two wider wings. The removal operation is quick and easy: manually or using common pliers, visitors can enjoy a tour in any season thanks to the pre-incision of the fins.