August Smart Lock 2nd Generation – Dark Gray, Works with Amazon Alexa – – Amazon.com
Details:

Control your August Smart Lock, using Siri on your iPhone or iPad

Apple HomeKit provides an easy, secure way to check your lock’s status and lock/unlock your door. It’s everything you love in the August Smart Lock, now with Apple HomeKit features.

Installation is so easy Battery Operated Nothing to wire or connect. When batteries need replacing, you’ll be notified by the August app. Connects via Bluetooth Highly secure Low Energy Bluetooth (LEB) syncs the lock to your smartphone. Use existing hardware Your exterior door hardware stays the same. Replaces only the interior side of most standard deadbolts.