Yes they do and I have had no issues with either of my 4el 40m beams made by OptiBeam. John KK9A Wes n7ws wrote: Optibeam uses square tubing metric tubing. On 11/27/2025 9:33 PM, Gary Johnson via TowerTalk wrote: > Square metric tubing. No thank you. > > Gary NA6O > gwj at me.com