You do realize that the carrot has six modes of operation - half of which are vibrate only, right? From the manual:
Changing Settings
The Pro-Pointer AT has three Sensitivity settings and two detection settings:
Audio-plus-Vibrate or Vibrate-only (silent).
To enter adjustment mode, press and hold the button () for 2
seconds—indicated by a single beep followed by a dual-tone beep and
flashing LED. (Note: In Silent Mode, beeps are replaced by vibration pulses.)
The first button press after entering adjustment mode indicates the current
setting. Repeatedly press the button to cycle through the 6 settings:
1 beep = minimum Sensitivity, with audio
2 beeps = medium Sensitivity, with audio (Default setting)
3 beeps = maximum Sensitivity, with audio
1 vibrate = minimum Sensitivity/Silent
2 vibrate = medium Sensitivity/Silent
3 vibrate = maximum Sensitivity/Silent
To exit adjustment mode, press and hold the button for 2 seconds—
indicated by a dual-tone beep (dual vibrate in Silent Mode), or wait 5 seconds
for automatic exit
Hope his helps.