The button (1) has a surface (3) provided with plate ribs (4) in a projected manner and constituting of anti-skid elements, where the plate ribs are arranged in a set of series of ribs(5) evenly spaced around periphery of the surface. Each rib is formed in chevron shape with point directed to a central area of the surface. The series of ribs is adjacent to each other, so that assembly of an upper surface of the surface is covered by the ribs.Ce plot (1) comprend une surface (3) pourvue de nervures (4) en saillie constituant des éléments antidérapants.Selon linvention, lesdites nervures (4) sont disposées selon une pluralité de séries (5) de nervures régulièrement réparties sur le pourtour de ladite surface (3), chaque nervure (4) ayant une forme en chevron dont la pointe est sensiblement dirigée vers la zone centrale de cette surface.
