It just works very well - a nice tight seal is achieved with the plunger (plus it sounds kinda cool when you take it out and put it back in) and all of the materials appear and feel like something of high quality. My only nit is the gasket around the glass lid tends to push the lid open at times but I can get a seal by pushing then twisting the lid onto the canister. I have 2 of these (1 for coffee and another for tea) - depending on my future needs, I would definitely buy more. Kitchen Barista's service has been excellent!