So I just finished my recone on my HDC3-15 copper D1 and could not figure out which dust cap to use. So I started looking at what I could use that would make it a little different from everyone else. So hre is how it went: First thought Second thought And the final, which is how I believe Sounqubed should be selling/shipping the subwoofers I took their 8 inch carbon fiber cap and trimmed it down to 6 inches to fit in the original cap area and "I like it alot".