Black draws a hard line around a shower; gunmetal draws a softer one. Gunmetal shower heads and rails are a deep brushed grey, so they give a dark, modern outline without the stark contrast of matte black against white tiles.
The difference shows most in two places. On pale walls, black looks graphic and gunmetal looks calmer. On water marks, gunmetal is more forgiving, because pale mineral spots stand out less on grey than on black. If you want strong contrast, compare black shower heads. If you want dark without the drama, stay here.
Some product titles spell the finish name slightly differently, but every piece on this page is the same gunmetal finish. The range includes rain shower heads, sliding shower rails, hand showers on wall brackets and twin shower sets. Shower heads and sets are WELS rated and sold at trade prices.