Abstract: In a mechanism for extending or retracting a telescopic unit, the plurality of interconnected cylinders includes an extension passage, a retraction passage and a flow-through passage interconnected to provide a flow path of a retraction signal from the first to the last cylinder and sequencing means for transmitting the retraction pressure signal sequentially from the last cylinder to the first cylinder to initiate retraction from an extended position beginning with the last cylinder. A poppet control check valve provides a position sensitive means to transmit the retraction signal to the next cylinder in the cycle. The sequence control valves and hold loading valves were formed integral to each of the cylinders. The load holding mechanism prevents unintentional extension and retraction movement under the action of the load for each of the cylinders.