The third model to use the Ruston-Bucyrus 10-RB casting was the Mobile Crane which had it mounted onto the AEC Sunderland cab and chassis which Benbros had already used on several models in the Qualitoys range. 

Both the body and jib of the crane as well as the cab and chassis of the Sunderland truck were 'from stock' so the only new casting was the platform on which the crane sat and to which it was rivetted. The platform was an angular unit but fitted firmly on the chassis with a front tab and rear rivet. Just behind the cab a cradle was included for the jib to settle when lowered.

Benbros used the second variation of the Ruston-Bucyrus 10-RB crane for this model with a pinned jib coupling and unpainted or black painted metal handles which were usually both on the right-hand side but sometimes one on each side.

As with previous models, the 'Sunderland' truck was painted bright red, the crane crimson-red & yellow with a dark-green jib, and the platform a bright yellow. '10-RB' decals were added to the crane, 'Ruston-Bucyrus' was cast on the back and 'Benbros Made in England' included underneath. 

The wheels were '6-bolt' metal painted red, yellow or pale-blue, or unpainted with large hub-covers similar to Zebra Toys wheels, or finally '6-bolt' yellow or red plastic, all fitted with black treaded tyres.

A bright red & yellow shared box was created for both the Mobile Crane and Mobile Excavator with the model names in large panels above or near model illustrations. On one of the end-flaps a blank section was left for the model details to be added which for the crane was just 'M CRANE' .

Because of its good play value, the Mobile Crane in mint condition is now a scarce model and will fetch a premium at auction.