The reverse transcriptase (RT) in the Template Switching RT Enzyme Mix adds a few non-templated nucleotides after it reaches the 5' end of the RNA template. These non-templated nucleotides can anneal to a template switching oligo (TSO) with a known sequence, prompting the reverse transcriptase to switch template from RNA to the TSO. The resulting cDNA contains a known sequence (complementary to the sequence of the TSO) attached to the 3' end. This feature can be utilized in a variety of downstream applications, such as cDNA amplification, 5' RACE (rapid amplification of cDNA ends), and 2nd strand cDNA synthesis.