Colour: lead-gray, it has a hint of blue in it, denim-like.
Material: woven nylon. Edges and holes are laser-sealed so all should be smooth. Hardware is kept in place by stitching. End pieces of the stitches can be melted and pressed flat with a small flame.
The buckle is attached with a push pin, so you can replace it with a buckle of your watch-brand.
Buckle and loops are 316L steel, with a brushed finish.