Beware how much current the adaptor can deliver vs how much the receiver wants.
Also beware of the regulating properties of some cig.plug adaptors... some are nothing more than a set of diodes that gets put inline on the + wire, each dropping about .7V, but exact drop depends on current drawn, the adjustable properties being the number of diodes getting pur in series. They typically work fine for stuff that normally runs on batteries (as they're normally designed for a fair swing in supply voltage - fresh vs almost dead batteries), but might be harmful for items expecting a better regulsted voltage....