A replaceable, wet-set tactile warning surface unit having a body defining an upper surface and a lower surface, the body defining a series of raised projections on its upper surface, and defining a plurality of spaced through-holes from the top to the bottom surface, in which the raised projections are spaced from one another and the through-holes are located between projections. An anchor member such as a threaded insert is coupled to the bottom surface of the unit member directly below each of the through-holes by fasteners such as bolts that pass through the through-holes.