Coolest, the company behind a popular Kickstarter-funded cooler, is now selling its product for $499 on Amazon in an effort to raise enough money to continue producing new units. The news may frustrate Kickstarter backers, who were promised the product in February of this year. Coolest said today it now plans to deliver the last shipment of coolers to Kickstarter backers by April 2016.

In a video uploaded to YouTube, CEO Ryan Grepper said the Amazon sale is to "keep the lights on" and "make certain that every single backer's Coolest can get made and shipped." The problem lies in the cooler's blending motor, which is made by a supplier that's currently on strike, he said. Coolest has been unable to find a viable replacement.

Kickstarter backers are furious the Coolest is selling on Amazon

Coolest customers aren't happy. In fact, 1-star Amazon reviews are flowing in from furious backers questioning why the units are not shipping to backers first. At more than $13 million in funding in exchange for around 60,000 coolers, the Coolest remains the second highest-grossing Kickstarter campaign in the crowdfunding sites' history behind the Pebble Time smartwatch. The Coolest was advertised as a Bluetooth-enabled, speaker-equipped cooler that could blend cocktails, play music, and store 55 quarts-worth of beverages.

Grepper was forced to announce the delay after testing on another blending motor indicated it could not meet the Coolest's required standards. Grepper says the company is looking into a replacement, and it’s unlikely the original supplier will end its strike in time. Even if a new motor passes the company's abuse testing process, it may take up to four weeks for a supplier to make them at volume.

Coolest says it spent $2 million on design and engineering

This isn't the first snag for Coolest. The product's original ship date was slated for February 2015, but Grepper was forced to push it back to July to add new features and give the operation time to ramp up production. The company began shipping in July of this year, and has since sent out tens of thousands of units. Yet many more backers remain.

In an interview with The Verge, a company spokesperson said Grepper will be posting an update later today explaining how Coolest has spent the $12 million it earned from Kickstarter, which itself takes a 5 percent cut of the total amount alongside 3 to 5 percent in fees for its payment processor. For instance, the company says it has high shipping costs to bring the 39-pound box containing every Coolest cooler to the company's headquarters in Portland, Oregon, from which it then sends the cooler out around the globe. Coolest also spent $2 million on design and engineering alone, it said.

The company confirmed it will continue shipping to backers daily even as it sells coolers at full price online. Coolest has not decided how many coolers it will sell on Amazon.

Update at 1:25PM, Thursday, November 19th: Clarified that Kickstarter's payments processor takes anywhere from 3 to 5 percent of a total campaign's earnings in fees alongside Kickstarter's 5 percent cut.