Flexible Concrete Vibrator Shaft with Quick Disconnect Coupler inner core is made from extra-high carbon steel wires with casings made from tough abrasion resistant neoprene rubber, reinforced with multiple layers of high tensile wire braiding with a hardened flat steel liner. This construction makes our Flexible Shafts rigid enough for driving into the stiffest concrete without kinking yet limber and non-slip for easy and effective handling. Our Flexible Shafts are interchangeable on all OZTEC power units, are reversible (doubling their service life)