The US-240 is what I’ve been using in my house for ~15 years. Its a base switch that support a number of different types of face plates. The face plates have anywhere from 2-8 buttons and each button can be programmed similar to programming a red switch single, double, triple, … click.
On the base switch there are 8 buttons which the face plate can interact with.
Here is the webpage for the product: Simply Automated -- Universal Dimmer Controller Base -- Model: US2-40 (click on the data sheet on the page to get some better pictures).
I’m considering shifting my house to Zigbee and have been following the Red discussion quite closely.
I’m not sure what is happening but I believe Simply Automated is going out of business. Their switch all support UPB. PCS Lighting created the protocol and is still in business. I’ve found UPB rock solid in my house. It’s just with a single manufacturer I’m feeling the need to upgrade. BTW I’m the author of the UPB integration for Home Assistant.