whats does Component Systems speakermean vs just speakers?

Also the speaker Depth is 1.8". But all the ones i look at hive a higher numder for depth.. Will they still fit aslont as there 6 1/2?

 

A component system is when the woofer and the tweeter can be seperated.These speakers come with a seperate box that has the crossover components in it so that the right sounds go to the woofer and the tweeter. In a normal coaxial speaker the tweeter is permanantly mounted in the center of the wooferand the crossover is mounted in the speaker. The component speaker system is considered a better way to go by most people because the tweeter can be located away from the woofer and in a better location to be heard.