It works like it says. But be warned it starts vibrating on the third ring.

It powerful vibrator

Work like a charm, hard shake wakes me from sleep

This thing is very handy. I am a deep sleeper, and could never hear my phone, with this thing, I wake up when I am called in the middle of the night.

Purchase this because I have college kids and sometimes I'm in a deep sleep and don't hear my cell phone....you definally cant miss this vibrating under your pillow

I am deaf and live alone in a rural N California forested area with high fire danger. I'm off-grid, no land line phones, just cellular service here and the closest neighbor is almost a mile away. I have a cochlear implant for hearing which works great when I am awake but I have to take the sound processor that hooks over the ear off to sleep. I've been looking for a ringer/flasher for my cell phone to wake me in emergencies. I was worried that the Serene Innovations ringer/flasher alone might not wake me out of a deep sleep so I also ordered the bed shaker accessory. Bed Shaker is a little misleading, it's more of a heavy vibration/pulsing. I just keep it under my pillow. It's slim enough that I don't feel a lump under the pillow. So if I have rolled over with my back to the flasher on the bedside table the shaker will still wake me every time. I highly recommend both.I have registered for text alerts with my county Office of Emergency Services and have programmed my phone with a custom vibration for their texts and the ringer/flasher to recognize the custom vibration. This eliminates nuisance texts, email alerts and voice calls from waking me except for important contacts I assign the custom vibration to. Instructions for this feature are in the manual .

to help me wake up.

these things help when you are hard of hearing!

I love it