If you were to look at the picture above and think that there is 2 7002’s and 1 7002T, you would be wrong. There are actually two 7002T’s and only one 7002.
Looking at the back of the alarms, you can see that the middle one is actually a 7002T. This alarm is some sort of weird cross-breed between a 7002 and a 7002T. I would say that it is 75% 7002 and 25% 7002T.
Has anybody seen this weird 7002/7002T “combo” before?
But here’s the actual story behind the 7000 series. The 7002 and 7002T were released at the same time, both with an open grille. The only difference between the two is that the “T” model has screw terminals instead of wire leads (the “T” stands for terminals). Around 1985, the grille was redesigned; and shortly thereafter, the 7002 was discontinued because Wheelock probably figured the 7002Ts were easier to wire up.