If the dress code is Black tie, well then the cummerbund and bow tie should indeed be black. But perhaps you're going to a dance or another dinner jacket event, like a new years party. In that case, this dark green cummerbund with its matching bow tie will be the evenings style victor.
All the products of this color that I bought have a much shinier color than the picture and reflect blue-purple when the light hits them. Not recommended in this color if you want dark green. The belly belt was a little better though as it didn't shine as much.