Just acquired one of these in a trade. Light is in transit as I type. Anyone have any info on this besides it being an one of the original Surefire lights?
It is the tactical version of the model 6R. The 7Z was originally shipped with the B65 rechargeable battery, charger and Z29 spacer and R60 lamp (long discontinued). You can use the B65 rechargeable battery to power a P60 lamp or two CR123's and the spacer with a P60 bulb.
I've moved on from the original B65 battery. I use 3 CR123's and take up the remaining space in the tube with a homemade cut-down dummy aluminum 123. I run a P90 lamp. It works great. If it comes with the original tailcap, which will be marked "7Z" you may consider replacing it with a newer lock out tailcap.
This is the 123 spacer I purchased and cut down.
Insert 3 CR123's into the 7Z. Measure the remaining space. Cut down the spacer to fit. Keep the nipple/positive end and cut off the remainder. Optional: I used shrink wrap on the cut end to clean it up a bit. If you use shrink wrap, make sure you leave enough bare aluminum exposed to make contact with the tailcap spring.