Endcap for Yakima FourTimer bike rack

Yakima FourTimer four-bike platform rack comes with endcap for maintube of both 2+2 sections, but when only using the two-bike section the included endcap doesn't fit. Print this to cap the maintube when using only the two-bike section. Sorry no bottle opener on this one!

I designed a retaining tab into the endcap to hold it in place using the existing slot. When I first printed this and tried to install, the tab cracked at the base due excessive bending. I've since reduced the height of