As a major retailer of single-serve bottled water, Dallas, Texas-based 7-Eleven Inc. is giving away free 1.08-ounce bottles of Mio Energy Black Cherry liquid water enhancer at participating 7-Eleven stores from midnight to 11:59 p.m. today, while supplies last. No purchase is required to receive the free offer; however, consumers must be older than 18 in order to participate, the company says.

"Our customers love coupons and freebies, and they are giving us lots of great feedback and suggestions on our offers," said Nancy Smith, vice president of marketing for 7-Eleven, in a statement. "We're always looking to deliver on our guests' wants and have partnered with Mio for this free offer as a result. People should check back often, both in-store and on the 7-Eleven app, because you never know when one of these special offers might pop up."

Regularly priced at $3.99 a bottle, Mio Energy Black Cherry, a product of Northfield, Ill.-based Kraft Foods Group Inc., contains 60 mg of caffeine in each serving. Each 8-ounce serving of Mio Energy-enhanced water contains an amount of caffeine equivalent to a 6-ounce cup of regular coffee, the company says.