DualClock 2 adds a second time zone's clock to your Lock Screen
Amazon.com: Super Loud Alarm Clock with Bed Shaker, Vibrating Alarm Clock for Heavy Sleepers Hearing Impaired Deaf Teens, Dual Clock with 7.5'' Large Display, USB Charger, Dimmer, Snooze & Battery Backup :
Dual Time Zone Clock City/state/country Sign Family Multiple - Etsy
MIUI 9.8.5 adds a dual clock and prepares an under-keyboard shortcut bar and "Dual WLAN acceleration"