What model of smoke alarm is this?

Do you know what model of smoke alarm this is? The one on the ceiling that they start to see how the kids respond to it. It makes an interesting sound. Kind of like a siren sound.

BRK 77R

What I can’t believe is those two girls barely flinched when it (squealer horn) when off. The one girl said “stop” and wanted to fall back to sleep. I would have been out of the house like a bolt of lightening.

Honestly if I had heard that I probably would have a massive freakout and lock myself OUT of the house.