National Time & Signal Corporation
Manufacturer of analog and digital clocks, master clocks, and large outdoor clocks for businesses, schools, and other institutions.
http://www.natsco.net

Global Union Industries Co Ltd
Manufacturer of clocks such as wall clocks, LCD clocks, frosted translucent alarm clocks and personal alarms.
http://www.globalunion-ind.com.hk

How Stuff Works: Digital Clock
When you need to know the time, it's about a 50-50 chance you'll turn to some LEDs to find out. Ever wonder what goes on inside a digital clock or wristwatch? Find out about this basic digital technology -- and learn how to create your own digital timekeeper.
http://www.howstuffworks.com/digital-clock.htm

Electric Time Company, Inc
Electric Time Company of Medfield, Massachusetts, USA, manufactures quality standard and custom made clocks. We are the world's oldest manufacturer of tower clocks and street clocks
http://www.electrictime.com/

Moser-Baer SA
Manufacturer of industrial time systems such as master clocks, time centers, indoor and outdoor clocks, facade clocks, GPS and DCF radio code receiver, NTP time server and synchronisation software.
http://www.mobatime.com

Ocean Clocks
Ocean Clocks produce unique tide clocks that are designed and localised for specific ports, coastal towns and regions of many countries.
http://www.ocean-clocks.com/

Clocks of Rocks
Handcrafted and imprinted granite, slate, and stone wall and desk clocks.
http://www.clocksofrocks.com/

Lenoxx
Makes mass market portable digital, cassettes, radios and CD players, clocks and phones. USA.
http://www.lenoxx.com/

Litech Electronic Products Limited
Manufacturer of a range of digital clocks, and watches. Based in Hong Kong.
http://www.litech.com.hk

Sanabic
Supplies digital clocks, telecommunication products, hardware and software engineering. United Arab Emirates.
http://www.sanabic.com