1) For all critical parameters set your ranges wide enough to include all possible acceptable material. This is true for all appropriate parameters like mean diameter, standard deviation, % solids, % magnetite, and surface titration (when necessary).

2) Remember to make those ranges wider than you think possible so you don't have to fix specs later. (Testing of pre-shipment sample for each lot will uncover lots which do not meet operational spec.)

3) Do not include our stock code number in your internal specification, because that number will change with every new lot of material that is made for you. (Including the stock code number will require you to keep re-writing your spec with each new lot number.)

4) If you can let us know how much you expect to use in 1, 2, or 3 years, we can make your material at the appropriate lot size and reserve that lot of material for you.