FAQ: Should I use the siRNA Marker, since I want to know the size of a single stranded RNA molecule? Should I denature the marker before I run it on the gel?

No. The siRNA Marker is used to measure the size of double-stranded RNA molecules. For measuring small single-stranded RNA molecules, we recommend the microRNA marker (NEB #N2102S), which is used for electrophoresis on a denaturing gel.