What is a necessary feature for hydraulic outrigger jacks?

A necessary feature for hydraulic outrigger jacks is the integral holding device. This component is crucial because it ensures the stability and safety of the crane during operation. When the outriggers are extended to provide additional support and distribute the crane’s weight over a larger area, the integral holding device securely holds the jack in the extended position. This prevents accidental retraction or failure of the outrigger during lifting operations, which could lead to dangerous situations such as tip-overs or equipment damage.

The other features mentioned, while beneficial, do not serve the same critical function of maintaining the outrigger's position and safety during use. Quick-release levers facilitate the fast deployment or retraction of the jacks, weight gauges provide information about load distribution, and color-coded controls help operators identify functionalities easily. However, none of these features are as essential for ensuring the mechanical integrity and stability required for safe hydraulic outrigger operation as the integral holding device.