Customers will be able to take a picture of a fastener, and Amazon will identify and send it.

Online retail giant Amazon is rolling out a new smartphone app called Part Finder, which will allow users to order small parts such as screws, nuts, bolts and other fasteners without a trip to the hardware store. The computer-vision technology behind the new app can identify more than 100 types of fasteners.

Here’s how it works: Say you find yourself short a small part on a job. You simply take a picture of the part, placing it next to a penny for scale, and send it to Amazon through the Part Finder app. From there, you are directed to a parts catalog where you can order the part for delivery.

The feature is designed to help Amazon compete with the big-box stores and smaller hardware stores that dominate the DIY market.