E-books had been around for a while before Amazon launched the Kindle. But the portable reader proved to be just the spark that digital reading needed to take off. Can Jeff Bezos wave his magic wand again with online grocery shopping? If so, then it might be because customers waved a magic wand of their own.

Much like the Kindle is a front-end device for Amazon's e-book business, Amazon Dash is a new front-end device for Amazon's same-day grocery service. If you subscribe to AmazonFresh, then Dash is going to make a lot of sense. The small wand has voice control and a built-in barcode scanner, and makes updating your grocery list a piece of cake.

So if you're baking cookies and run out of flour, just grab the Dash, hold down the voice button, and say "flour." Or if you want to order more of the specific brand you just ran out of, press the barcode button and scan the empty bag. And though Dash doesn't automatically order the items you add, they will be waiting for you in your queue the next time you log onto AmazonFresh.

Amazon has a habit of selling consumer gadgets for dirt cheap, and making all of its money on the content you consume for the gadget (see Kindle, Kindle Fire, Fire TV). As you might expect, we're seeing the same thing with Dash – only here it's being taken to a new extreme. The Dash wand will be free for AmazonFresh customers, provided they can snag an invite.

The only catch (well, apart from AmazonFresh's US$300 annual cost) is that very few of us can even use the service right now. As AmazonFresh is only currently available in the Seattle, Los Angeles, and San Francisco areas of the US, this might not mean a lot to you just yet. But it is a sign that the company has big plans to disrupt the grocery business. With that kind of ambition, it might not be long before the service starts popping up in other areas.

You can watch the video below for more info, and, if you live in one of those select AmazonFresh areas, you can sign up for an invite at the product page below.

Product page: Amazon