About 1" x 1", and
very light for you weight weenies!
Kelley e-mailed me the following:
"Please note that the tool is designed for use on a 9 speed chain. It will not collapse the link (squeeze it) unless you also squeeze the sides while inserting the tool. Because the master links have a machined grove to hold the sides in place, which means to open the link you have to press the sides together with your thumb and forefinger while pressing the tool into the link."
I've heard from others who bought a Squeeze Link, and it will work on 10 speed chains but it's a tight squeeze. As for SRAM only or all master links, I don't know. You'll have to try it. The $4.00 price includes shipping, so I'm sure he's not getting rich from selling these.