help me with x-over settings.

[rollerdj 0]

hey everyone. i got a set of x-overs and was wondering if u can help with the settings. when i take the cap off there is a wire that goes to eather "A" or "B" plug. there is also another wire that can go to low, med, can't remeber the third one, and loud. what are all these for. thanks for your help guys.