March 2006 "Z" only 24" min 26 AWG wire leads OPB740W or OPB740WZ No windows OPB741W or OPB741WZ Blue windows OPB742W or OPB742WZ No windows OPB743W or OPB743WZ Blue windows For RoHS compliant devices add "Z" to the end of the part number: OPB740WZ