The MST515DYE carries the same drop-crotch construction as the black version but the grey dye process changes the surface of the fabric. Dyed cotton has a different hand than undyed: the dye penetrates the fibre and can slightly stiffen the surface feel during first wear, softening progressively with wash and body contact. In grey, the flame doubleface cotton and linen inserts read with less tonal separation -- the grey dye unifies the two fabrics visually while their tactile difference remains distinct against the skin. The linen insert zones feel drier, cooler, more open to air at the points where the body generates heat. The drop-crotch silhouette distributes the fabric low across the thigh; nothing pulls at the seat or rides up through movement. Raw cut hem. Four-pocket configuration. Nothing added to the surface.