This is my favorite new toy. It's manufactured by the Gill company, and I got it from Dick Blick for around $20.00. Very well worth it. It's a metal clamping system for wringing all the paint out of each tube, and it works just great. I can hardly believe I've been painting for almost three years now without one. They are also available in plastic. The link is here: tube wringer
We'll put it in the category of great tools!