The siRNA marker (NEB #N2101S) is consisted of three synthetic non-phosphorylated RNA duplexes. This marker is used for measuring the size of small dsRNA molecules such as siRNA. The siRNA Marker should not be denatured prior to electrophoresis on a native gel. The microRNA marker (NEB #N2102S) is composed of three synthetic non-phosphorylated single-stranded RNA molecules supplied a denaturing buffer. This marker is used for measuring the size of small ssRNA such as microRNA molecules. The microRNA Marker is used in denaturing gels and stained with SYBR® Gold (Invitrogen) for visualization. This marker can also be detected via hybridization using the provided biotinylated probe. In addition, this biotinylated probe can be labeled with γ32P-ATP using T4 Polynucleotide Kinase (NEB #M0201S), since the probe has a free 5’-end.