24PCS Decorative End Cap Plug - Fits All Conical Truss End Connections | Set of Four

The ProX XT-ENDCAPX4 End Caps are smooth, rounded aluminum end caps that provide clean stylish ends to Trussing.   

ProX Truss products utilize industry standard dimensions to be compatible to connect to, and work with, many other manufacturers F31/F32/F34 trussing products with conical connectors. ...
https://www.proxdirect.com/products/view/757/24PCS