Contains high titer Cre-excisable polycistronic (OKS) lentivirus that expresses modified stem cell cassette. MilliporeSigma™; Mouse STEMCCA Cre-Excisable Constitutive Polycistronic (OKS) Lentivirus Reprogramming Kit comprises of the three transcription factors Oct4, Klf4, and Sox2 (OKS) separated by the self-cleaving 2A peptide and IRES sequences.