What is the difference between multi-mode and single-mode fiber?

"All" Fiber Network Switch - SG24424M   

4 Channel Fiber Optic Video Multiplexers for Fixed Analog Cameras.

MultiMode vs. SingleMode Fiber Optic Cable

Pick a Port" 10/100/1000 Modular Network Switch - 11 Different Modules Available - All Fiber Solutions too!

PoE (PoE+) Fiber Optic Switch

HDMI Video to Fiber Optic Installation Kits

Video Distribution Amplifier for CCTV, (16 Inputs, 32 Outputs)