NBS Aluminium Tube is available in a range of telescopic sizes for repairs and manufacturing antennas.  This aluminium has a host of uses including Medical Labs, Vehicle fuel and oil lines or anywhere a light weight strong tube is needed.

Part numbers for 6.35mm  tube is NBSAT+635 (tube diameter) making it NBSAT635 

Price is for a 2.75meter length of sturdy 1.42mm walled tube