E6560 includes M-MuLV H^– reverse transcriptase in the enzyme mix, while E6300 includes wilde type M-MuLV reverse transcriptase in the enzyme mix. M-MuLV H^–  reverse transcriptase is a mutant M-MuLV Reverse transcriptase with reduced RNase H activity and increased thermostability. The enzyme is active up to 50C, providing higher specificity, higher yield of cDNA, and more full-length cDNA product.