Strange, I know, I'm building some 3d printed tester caddies to complement my Salifert test caddies but I don't have any to verify the dimensions. I would need a set with at least one of all the parts (vials, sryinge, reagent, checker) to double check the dimensions in the real world and take some photos. I'll send you $15 if you can ship it (as cheaply as possible of course).