The LaMotte® TesTabs® 6903A-J are Chlorine DPD #1 Instrument Grade Tablets 10 per Sheet 100 per Pack. LaMotte has developed a rapid dissolve instrument grade DPD tablet system. Instrumental analyses require a clear, particle-free testing solution. In the past, it was necessary to use a crusher to dissolve the instrument grade tablets. Now, free and total chlorine samples can be done with instrument grade tablets that dissolve without crushing. It is a genuine LaMotte product.