I've been using these for about 10 years. They work very well. Grease the piston well (I use Crisco shortening.) Be careful when loading to try and get as much air out of the tube in order to avoid air pockets in your sausages. I was amazed how little water pressure is needed to push out the meat. A little awkward at first but I've been happy with it. When re-loading, the piston should travel back to the starting position. I have to hold the stuffer up as it drains and the piston moves as it should. The tinted see through model is better so that you know how much meat is left when changing casings.