The G1581 (GBM‑2100‑1ADR) boasts Tough Solar charging and Bluetooth® Smartphone Link, allowing automatic time sync, app-based setup, world time functionality, reminders, time & place logging, and phone finder capabilities https://saicreationswatches.com/products/g1581-casio-g-shock-gbm-2100-1adr-analog-digital-watch-men