What kind of power does the Ring Outdoor Cam Plus (Plug-In) use, and does it need batteries?

It uses an Indoor/Outdoor USB-C Power Adapter for continuous plug-in power, so there is no battery to recharge.

Does the Ring Outdoor Cam Plus (Plug-In) support two-way talk and a security siren?

Yes. It includes two-way talk with noise cancellation, and you can activate a remote-controlled security siren directly from the Ring app.

double click image to zoom in

Ring Outdoor Cam Plus (Plug-In) - 2K Indoor/Outdoor Security Camera, Two-Way Talk, Security Siren, WiFi 6, Customizable Motion Zones, Black

2K VIDEO WITH WIDE FIELD OF VIEW: A 2K sensor paired with a 160-degree diagonal (140-degree horizontal, 80-degree vertical) field of view captures sharp, detailed coverage of wide outdoor and indoor spaces alike.
RELIABLE PLUG-IN POWER & 10-MINUTE INSTALL: An Indoor/Outdoor USB-C Power Adapter delivers continuous, cord-free power with no battery to recharge, and setup on a vertical or horizontal surface typically takes about 10 minutes.
TWO-WAY TALK WITH NOISE CANCELLATION & REMOTE SIREN: Speak with visitors clearly through two-way talk with noise cancellation, and activate the remote-controlled security siren directly from the Ring app when something doesn't look right.
ADVANCED MOTION DETECTION & CUSTOMIZABLE ZONES: Real-time, motion-activated alerts keep you informed the moment activity is detected, and Customizable Motion Zones let you focus notifications on exactly the areas you care about.
WIFI 6 DUAL-BAND & WEATHER-RESISTANT DESIGN: Dual-band 2.4GHz/5GHz WiFi 6 connectivity delivers a fast, reliable connection, while a weather-resistant build rated -4F to 122F keeps the camera running through rain, heat, and cold.