This is a very simple polygonal trap that is to be used in conjunction with most (eg kerr, ball) wide-mouth canning jars and the associated threaded band. I have had the best luck with these using a little red wine or red wine vinegar and a drop of dish soap. You can also add a piece of cut up fruit to increase the fermentation. The trap pictured is black - I'd suggest using a lighter color, maybe even white. For some reason they don't like the black trap as much as the white one I printed.