Neil, yes the trays are made to match the two differant battery configurations you can make so first look at your packs to see which tray you need or you will be forced to use the tray by flipping the pack upside down which can be a problem if you hard-wire your packs or resoldering your packs up to fit the tray which I do not recommend. Look at your packs from a top view and match them up to whichever tray has that configuration. I beleive the promatch site tells you this.