HelloKlick & 360 Klick Quick Click buttons
I bought mine from Dealextreme:
This one is sleek and has a nice contrast of black/silver. Looks great on the Razr HD, like it was meant to be.
Comes in a box with a holster that attaches to key ring and/or headphones.
This one is a bit taller than the other one and is all silver. Looks good on the Galaxy S5 (sorry no pics, the phone owner is sleeeeping) and works well with the S View case.
Comes in a faux leather zip case and a holster that attaches to key ring and/or headphones.
When I got these buttons I was disappointed that they would not work with the Razr HD at all, no matter which rom I was on, but worked fine in all other phones (Even the Atrix 4G running JB!). I eventually stumbled upon this thread and found the way to fix it:
Basically you install the Key test app in that thread and find out what the click is being interpreted as by android, in my case it was "BUTTON_1" with an address of key 256. This is wrong, we want the button to be "HEADSETHOOK". (Your button number will likely be different depending on phone model)
I opened /system/usr/keylayout/Generic.kl in root explorer and changed the "BUTTON_1" to "HEADSETHOOK" next to key 256, saved and rebooted.
(this button wasn't assigned even in stock roms)
Works great now except for long press...Google now likes to take this default over, even if defaults are cleared. My room mate uses Headset Button Controller
to get a ton of shortcuts. I just use the basic HelloKlick app