If you are OK with a weather radio that does NOT have SAME technology (where you identify the specific county/region SAME code(S) that you want the radio to alert for), then ...

The Midland HH50/51 Pocket Weather Alert Radio is about the smallest and simplest weather radio available right now.

It has four buttons/switches:

On the right side it has a sliding switch with three settings: OFF, ON (radio plays), and ALERT (radio off, but alarm sounds and radio comes on if an alert is sent).

When you slide the switch to ON (or ALERT) the radio scans and selects the strongest weather alert signal. If channel reception is poor, make sure antenna is fully deployed.

On the left side it has three buttons:
Top - Test/Channel Rescan button
Middle - Volume Up
Bottom - Volume Down

Test/Channel Rescan button details:
---With radio in ALERT mode, press & hold for 3 seconds to start the alarm siren. Press again to stop the the siren.

---With the radio in ON mode, press & hold for 1 second to have the radio rescan for the strongest weather alert signal.

BTW, the HH51 is the camo version, so if you drop it while in the woods Midland gets to sell you a new one. Nice feature! (just kidding ... I guess hunters like their camo ... I wish there were a yellow or orange version to make it that much easier to find).