eufy Security by Anker SmartTrack Card (Black, 1-Pack), Works

Ultra-Loud Alarm: Despite being only 2.4mm thick, Card can sound an alarm so loud you can hear it even if it’s covered.
Water-Resistant with Non-Replaceable and Non-Rechargeable Battery: Card can last up to 3 years and is safe even in the rain with its water-resistant coating.
Free Left-Behind Alerts: Avoid losing your belongings with instant alerts via the Find My app—with no added fee.
Find Your Phone in Silent Mode: Your phone rings even in Silent mode with just a double tap.
Share with Everyone: With the eufy Security app, you can let others know the location of your items too.
What’s in the Box: SmartTrack Card, Metal Clip, and Quick Start Guide.