I asked Sentry if they could have the 10V2T, 15V2T, or the 20V2T sirens custom manufactured with dual 920 Hz rotors, and they replied "yes." Any of their dual tone sirens can come with two 460 Hz, or 920 Hz rotors, as single tone models.
I would love to hear a 20V1T with dual 920 Hz rotors.
