What the ratings mean for fit
The AF210 frame is a DIN-rail-mount reversing contactor. The 30 in the code designates the number of power poles (three main poles), and the 11 after the dash indicates one normally open and one normally closed auxiliary contact built in. That's a common configuration for a reversing starter: the NO aux can seal in the coil circuit, the NC can provide electrical interlock against both contactors pulling in at once. On a panel build, this saves the space of a separate interlock module and the wiring of two contactors with a mechanical bridge.