QPR® 50lb 6690 Hot-Applied Crack Sealant is a flexible, rubber-like commercial grade product that is used to repair cracks of any length or width in asphalt pavements. It starts out as a solid, rubber block which is then melted in a special kettle and is heated to 375 degrees F. Once melted, the crack filler is applied to the cracks. The crack filler hardens up deep inside the crack, sealing out moisture from penetrating the asphalt. This prevents it from causing further crack development and promotes a long lasting repair and an attractive appearance.