The Collaborative International Dictionary of English v.0.48:

all-mains \all-mains\ adj. prenom.
   1. adaptable to all voltages; -- of a radio receiver.
      [British]

   Note: For power supplies, the term "switching" is used to
         designate ability to use more than one voltage as a
         power source. Typically, it is used for the ability to
         use both 110 and 220 volt AC sources. an all-mains set
         [WordNet 1.5]

WordNet (r) 3.0 (2006):

all-mains
    adj 1: used of a radio receiver that is adaptable to all
           voltages; "an all-mains set"