and I cant't seem to figure out what it is...

  It's from a filter and I managed to break one of it's "legs" of, this is the part:  

 Sorry, phone pic... looks like J5n J63  I have the electronics somewhat working (in my Fender) and connected the q switch where this part came of.  I bet Mica can tell what happens when I flick the switch to the on position... It has a big red sign next to it that says: DO NOT USE!!!

  If anyone can tell me what it is, I'd be very gratefull :-)

It's a capacitor.  
 
50nF (50 nano Farads) 63 volts.  
 
Usually on a Q switch, we change it to an axial type instead of these cute little box ones.

Thanx! :-)