Tanya,
I have been trying to research what is available out there. My goal is to find a light weight (for the dog) collar that has a tone only. What I have picked up from the research is some companies refer to page mode. This can be tone, or a vibrator. Dogtra seems to have coined the term pager and refers to a vibrator mode when they use it. So you have Tone, Vibrate, Nick (very short shock) and shock or correction (continuous up to 5 secs if you hold the right button down. I also know that the tone is not the same through all the manufacturers, some are quite subtle that only the dog will hear since it is around his.her neck, some are quite loud that I can hear from 50 yards.