Husqvarna's line of Excel blades are designed and tested to meet all aggregate conditions.The blades provide highly efficient, stable and convenient operation in trap-rock, chert, quartz and limestone concrete. Color coded according to the blade name and type of material it cuts, you will be pleased with the results and price.An anti-ravel skid plate comes with every blade. This allows for same-day sawing without chipping and spalling.BLACK- Ultra Hard Aggregate, non abrasive sand Available in the following Other Color Codes- See next pagesPURPLE- Ultra Hard Aggregate, non abrasive sand GREEN- Hard Aggregate, non abrasive sand RED- Medium to Hard Aggregate, medium abrasive sandORANGE- Medium Aggregate, medium abrasive sandYELLOW- Medium to Soft Aggregate, abrasive sand