Please note I know absolutely nothing about fans! (Or electricity etc, so please view the information on the unit in the pictures prior to making a decision). These came from a large lot of what we believe were mostly new medical equipment (these were in Medela Warmers) and were tested prior to selling parts (the complete warmer had low demand and not worth the shipping costs). Although we package these safely, you’ll actually receive 9 free (99 total units) just in case any issues.