Tetenal Superfix tablets are dissolvable tabs of fixer with a shelf life of more than 4 years, designed to let you mix up only as much as you need for any given batch of film. Each jar contains 20 tablets, which can be dissolved to produce 150ml of working solution each- mix as much as you need, and reuse as necessary (each 150ml mix can be used for up to 3 rolls of 35mm film). Its unique storage and portioning properties make it practical if you’re processing film every once in a while.