Material: titanium alloy, black stones. Vibration flash, remote sensing, unlimited distance worldwide. Connect to Totwoo App via Bluetooth, one-to-one pairing in the app, no need to worry about crosstalk, each pair of bracelets only matches each other. The bracelet will vibrate and flash when you receive an incoming call from the other party or send a video, picture or text to the app. Charge for 60 minutes, romance for 72 hours. Waterproof for life, technology art and romance all in one. Symbolizing the eternal sun and moon totem, it is a metaphor for the flash of love and unchanging commitment.