Used with Riboprobe(R) Systems to Monitor in vitro Transcription Reactions Can be used with SP6, T7 or T3 RNA polymerase SP6 RNA polymerase produces transcripts of 1,787 and 2,566 bases; T7 RNA polymerase produces transcripts of 1,065 and 2,346 bases; T3 RNA Polymerase produces transcripts of 250 and 1,525 bases