Amazon.com: 4PK Support Pole, Steel Telescopic Adjustable 3rd Hand Support System, Support Rod, Supports up to 154 lbs Construction Rods for Cabinet Jacks Cargo Bars Drywalls Extends from 49 Inch to 114
14ga Telescopic Square Steel Tube Dia. 7/16' on All Four Sides, Holes Center Distance 1' Galvanized Surface - China Square Steel Tube, Square Steel Pipe | Made-in-China.com
Steel Telescoping Square Tube Combo Pack 1-3/4" and 1-1/2" Telescope Tube x 12" | eBay