3D Model: An Extendable Bar. Thickness Dosn't Too Much But As Compact As Possible But Under 5cm Would Be Best. The Extension And Retraction Of The Bar Needs To Be Done Toolless From One Side As It Will Be Placed Against A Surface. It Will Need To Be A Thick Single Thread That Can Exert Force On Retracting The Length Of The Bar And Usable With One Hand. None Of The Mechanism Should Be Open On The 4th Side That Is Against The Surface And Preferably Only Open On The One Side That It's Operated From. The Total Length Should Start At 25+ Cm And Constrict To As Short A Distance As Possible But At Least 10cm.