Kaley Cuoco swears by this water bottle for her workouts

Kaley Cuoco welcomed her daughter Matilda in March and, having been able to resume her fitness regimen, she's recently shared a slew of videos and photos on her Instagram Stories of herself working out again with her trainer. But we professional shoppers discovered a delightful little Easter egg in her chronicle when the Based on a True Story mentioned how she stays hydrated during those sweat sessions: She uses the Coldest Water Bottle. Thanks to Kaley, we're now Insta-fans.

This 18-ounce water bottle is double-walled and vacuum-insulated to keep drinks cold for hours. A straw lid makes it easy to sip from.

Cuoco shared her testimonial earlier this week after a series of workout videos. The photo shows her holding up the bottle after her workout, writing that it's her "new obsession." She continued, "This is not an ad but OMG, keeps ice for like two days. It's insane and good colors. LOL very important."

What's the deal with this water bottle? Coldest lives up to its name by featuring double wall insulation to create an environment that keeps your beverages at the ideal temperature. The brand says it will keep drinks chilled for up to 36 hours and hot for up to 13 hours. The bottles, which come in a wide range of sizes, are made from 18/8 stainless steel that doesn't give a taste to your drinks or rust over time.

As Cuoco pointed out, these drinks come in 14 cool colors. Choose from more traditional shades, like white, black and a cool wood theme, along with funky shades like Black Leopard, Astro Purple. Cosmic Ice Glitter, even a Purple Moon Glitter option.

The popular 18-ounce bottle comes with a wide mouth lid with a straw, while the 36-ounce option features — a chug, straw and handle lid.

Cuoco isn't the only fan of these bottles. Plenty of Amazon shoppers swear it keeps their drinks cold. "I love my Coldest water bottle. It definitely keeps my water or beverages cold for a lot longer than other products I have used," shared a five-star reviewer.

A fellow happy customer said the bottle keeps water "cool all night long, no ice cubes required." And check this impressive testimonial: "It keeps cold things cold for many hours. I have it next to me at my bedside at night and there is still ice the next morning as if I had just filled it."

Going mega-sized? You'll get a wide mouth lid for one-handed chugging, a loop lid for easy toting, or a 'chug and shaker' lid that'll allow you to make a smoothie before taking it on the go.

If you have Amazon Prime, you’ll get free shipping, of course. Not yet a member? No problem. You can sign up for your free 30-day trial here. (And by the way, those without Prime still get free shipping on orders of $25 or more.)

The reviews quoted above reflect the most recent versions at the time of publication.