Make no mistake this is one beautiful piece of machinery. The photo bottom left shows the heart of the system - the hydraulics. The photo on the right shows the Dryden Trailer Home with the wheels completely off the ground on one side. This is controlled by a plug in switch. This reduces the chance of the rams operating during driving. All hydraulic cylinders have pilot operated check valve. What this means is they are almost fail-safe requiring hydraulic pressure to lower the unit. Unlike other units on the market - particularly USA imports, the cylinders are mounted outside the stays. This makes seal changing very easy indeed.