Didn't ATR make inverters to make 115 V, 60 Hz from car batteries? Perhaps this is for one of those uits. -John Brian Carling wrote: > Markings look like this: > > ATR Vibrator > Type 12427 > Serial 371065 > 12 Volts D.C. circuit > ATR Mfg. Co. Inc. > St. Paul, Minnesota > Made in USA > > Does this help identify them? >