Knock, knock…

If your family is anything like my family, good naps for the kids are hard to come by on family trips. General excitement, unfamiliar sleeping environments, and jet lag often work together to disrupt even the most necessary of afternoon siestas. To make matters worse, on those rare occasions when one of our girls actually does doze off, something inevitably wakes her up.

This why I am currently obsessed with the Knock Nanny, which debuted at the 2014 ABC Kids Expo in Las Vegas this week.

In a nutshell, the product is a universal doorbell cover that gives would-be sleep disruptors a stern-but-loving warning about waking the sleeping kid. The covers fit perfectly over doorbells at most vacation houses. They also fit nicely over many (but not all) doorbells inside luxury hotels.

Think of the product as the modern take on a handwritten note you’d tape to the door.

Because the Knock Nanny physically covers the doorbell, however, there’s no chance a would-be child-awakener can wake up the sleeping babe.

The device has 27 available decals you can affix to the front—stickers with cute slogans designed to give people the message to keep it down. Most of the slogans are PG; stuff like “Please knock softly,” and, “Shhh! Baby Sleeping.” I also like the one with tiny star icons that says, “Future Star Sleeping Inside.”

Perhaps the best thing about the Knock Nanny is the price: No matter where you buy it, you can get it for less than $6. Not a bad investment for a nap or two on your next big trip.

What are your secrets for getting kids to nap on family vacations?