Polyuréthane The production of holds using this material was introduced in Europe around 2010. This method of production provides very light and flexible holds and is so strong it is virtually unbreakable. Polyurethane is the ideal material for producing large climbing holds. The climbing holds available in polyurethane will have the following symbol: Polyester Polyester is the resin most often used for making climbing holds in Europe. Mixed with sand (resin mortar), it is colored and catalyzed then poured into a mold. Polyester resin climbing holds are heavier than polyurethane. This method of production is the least expensive and the climbing experience on this material is very similar to the outdoor rock. It is sensitive to breakage and has no flexibility. The climbing holds available in Polyester will have the following symbol: 4 fluorescent colours Yellow fluo Green fluo Orange fluo Pink fluoSize distribution ◄ ± 4 – 6 cm ► ◄ ± 1,5 – 2,5 inch ► ◄ ± 7 – 9 cm ► ◄ ± 1,5 – 3,5 inch ► ◄ ± 10 – 14 cm ► ◄ ± 3,5 – 5 inch ► ◄ ± 15 – 20 cm ► ◄ ± 6 – 7 inch ► ◄ ± 20 – 30 cm ► ◄ ± 8 – 12 inch ► ◄ ± 30 – 40 cm ► ◄ ± 12 – 16 inch ► ◄ ± 40 – 60 cm ► ◄ ± 16 – 24 inch ► Extra small 45- climbing holdsSmall 20- climbing holdsMedium 68- climbing holdsLarge 63- climbing holdsExtra large 72- climbing holdsXXL 42- climbing holdsMacro 48- climbing holds9 standard colours Blue RAL 5015 Purple RAL 4008 White RAL 9010 Red RAL 300 Black RAL 9005 Green RAL 3018 Grey RAL 7040 Yellow RAL 1023 Orange RAL 1024DDS : Digital Double Screw Digital has also developed its fastening system, the D.D.S. (Digital Double Screw), which allows CHC or FHC screws to be fixed indifferently. Screw lengths are also a problem that Digital wanted to simplify. The series fixing is systematically provided with only one screw length, which makes it possible to assume that the size S or M sockets are fixed with 40 mm screws. The size L or XL screws are fixed with 50 mm screws.