Metal springs are on their last leg in the mattress industry and Casper is hoping to put them to bed for good. As one of the premiere foam and gel supported mattress lines, odds are good that you have heard a Casper Mattress ad on your favorite podcast or streaming service over the last few years. One of the most popular lines are on sale today over on Amazon but you may want to act fast. The deal is part of Amazon’s Gold Box deals, marking the entry level Essential mattresses up to 20% off, that’s regardless of the size that you need.

This deal is only scheduled to last for one day, and while Amazon has run this promotion in the past, they usually sell out before the day’s end. If you are in the market, the Casper Sleep Essential Memory Foam 8.5″ Mattress in Queen is going for just $480 today, while the Casper Sleep Essential Memory Foam 8.5″ Mattress in King is selling for $580. That puts the Full Size at just $400 and the Twin and Twin XL at $280 and $320 respectively.

You’ll still get Casper’s 100 night risk free trial, so if you decide the mattress isn’t for you, you can let the company know and they will come take it from you. As an owner of a Casper mattress, I can say that I have recommended them to my friends and just like the ads say, I was surprised at just how tiny the box was when it arrived. I actually went all out when ordering mine, choosing the Casper bed frame and the Casper base, but many of my friends saved money using their own frame and support and loved their mattress just the same. This sale is for the entry level mattress, which doesn’t have the extra fourth layer that the traditional Casper has but it’s keeper just the same.

At the time this article was written, all six sizes were still in stock but that could change throughout the day. You can find all of the sizes and details right here on the promotional page at Amazon.