CoverPro 15 is the best synthetic underlayment to combine the value-added performance of synthetic underlayment with the roofing felt. CoverPro 15 provides the synthetic features you demand for fast, simple installation and robust performance under asphalt shingle roofing. Manufactured from 100% synthetic materials, CoverPro 15 is the engineered solution that finally offers the performance you need, at a price competitive with 15 Lbs. felt. Faster installation, better installed performance.