... 3.apply to air compressor WHZD-25A smart motor protector Main Function 1,Protect function:Overload,phase failuer,block,three phase current unbalance ... ,under-voltahe etc.2,Error display:With phase A,phaseB,phaseCworking ... dash ele dot comTHANK YOU FOR YOUR VISITING! NEW DESIGN!! WHZD-25A smart motor protector(CCC&CE&ISO9001)