An FB4 laser projector is one that is built with, or features any of Pangolin's FB4 control hardware (including FB4 External). These laser projectors were designed to be fast and easy to control, using a proprietary method of laser control called streaming mode.
Streaming mode allows the FB4 to connect directly to a computer via an ethernet port. Once connected, using streaming mode, you can directly control a laser light show projector from a PC using either Pangolin's QuickShow, or BEYOND software.
For even easier access and more control, Kvant laser projectors feature a special version of FB4 called "FB4-SK". This type of FB4 allows you to daisy-chain laser projectors using a built in switch on the back of the laser projector (which means there is no need for any sort of switch or additional hardware), FB4-SK also allows you to use special features such as "Color Balance Correction Mode", "Optical Bench",