Optimus MK-D is an audio door station that allows for two-way communication between a visitor and a resident. It can be used in a variety of applications, such as:

• Residential: Single-family homes, apartments, and condos
• Commercial: Offices, warehouses, and retail stores
• Industrial: Factories and other industrial facilities

The Optimus MK-D is a durable and weather-resistant device that is designed to withstand the elements. It features a built-in microphone and speaker, as well as a push-to-talk button. The device is also equipped with a volume control knob, so you can adjust the volume of the speaker to your liking.