The purpose of the SLAM Option is simply to give you the choice of saving some money on the two refill items you will likely need first if you are performing a SLAM (Shock, Level, and Maintain) on your pool. Generally, this option is intended for owners who are having problems with their water clarity, especially due to algae, and who will need to do more FAS/DPD chlorine testing. If your water is clear and you don't have to test often, you don't really need this. It is also ideal for owners performing a Baquacil conversion because of the high chlorine levels you will need to test. This set includes 10g of R-0870 DPD Powder and 2 ounces of R-0871 FAS/DPD Reagent.