For reference:
https://www.mcmaster.com/8974K97-8974K65/
72" long x 4" round aluminum stock. The Slonik covers are ~3/4" thick, so you get 72 (conservative) sets per $600 six-foot round stock. That gets you 18 sets of covers, that sell for like $400 each. The only reason I can see people tolerating a vendor purchasing $600 in materials and doing some generic cnc to it, and charging $7000, is because there is no other clip-on option.