2PCS Electric Thermal Actuator 230V 2W for Underfloor Heating Manifold Radiator. Easy to Install: 2-Rung short body ladder jacks can be easily attached to ladder; Easily adjusts to fit different shapes of ladders such as round, square, and D-shaped ladders; Height adjustable between 2 sections of ladder from 8.85" - 12.99".
eBay