They told us when we checked in that this card was for power. Ok, no problem. Thinking it worked like a hotel key card, I put it in the slot, pulled it back out and went about getting settled in (which included using the restroom). The lights went out while I was finishing up. It was 2 am. I realized then that I needed to leave the card in the slot to keep the power on. One more thing to note about the power. The light switches work in the opposite way. Up is off, down is on.