marker lights

so when u mark someone with a marker light, does that effect only work for the squad that used the marker light, or is it anyone who shoots at the marked unit get the bonus?

The squad that shoots a markerlight cannot benefit it.

Once one squad uses a markerlight "token", no other squad can gain benefit from that markerlight, it is considered spent.

I set out dice to indicate what I've marked, and remove them one at a time when I use them to keep things straight.

Believe me, I wish one markerlight could be used to boost the BS of multiple units, or lower an enemy unit's cover save to everyone shooting at it, but we can't; it's all one to one.

Just to mention though, that there are networked markerlights which do apply to the squad that fires them. (i.e. the very expensive markerlight drones or the ones found in sniper drone teams).