"Pyrovalerone is a DEA Schedule V controlled substance. Substances in the DEA Schedule V have a low potential for abuse relative to substances listed in Schedule IV and consist primarily of preparations containing limited quantities of certain narcotics."
i'm a layman here, so just googled it:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrovalerone
"Pyrovalerone is a DEA Schedule V controlled substance. Substances in the DEA Schedule V have a low potential for abuse relative to substances listed in Schedule IV and consist primarily of preparations containing limited quantities of certain narcotics."
He's talking about the derivatives (nicknamed Pyros because they're related to Pyrovalerone) like α-PVP, MDPV and others.