Well 2 boxes and a padded envelope greeted me when I opened my mailbox last night. I had to wait until I got out of work to open them, in them were these.
3 SmokeGard 907s (was only expecting one, makes the 60hz pulsing buzz), a New in the Box Montgomery Ward 83-7-1666-00 (with a leaking Montgomery Ward 9 volt battery, makes the typical squealer horn buzz), and a New in the Box GE Home Sentry SMK-6/M1 (sadly I mangled the box opening it, makes the warbling beep).
The insides of the Montgomery Ward. Looks like this is just a relabeled First Alert SA76RS or the BRK equivalent. What surprised me was just how potent the horn is, louder than my Sears 350.57045, and Family Guard FG777.
The insides of the GE. Never seen one with a black sensing chamber before.