New standard QD Double-girder Electric Crane is the renwed product of "QD",which is an intelligent crane.Its structure is much more reasonable and its assembly and property is much superior.Lifting capacity is 5t-500t(Gn),and the span is 10.5m-35m.and working system is A3 or A5 or A6 or A7.and ambient temperature no more than 40℃(Note the high temperature).