needs to be a regular magnetic ballast, designed for HPS, with an iron core transformer, not the electronic type. otherwise there are no other technical specs that i know of.
this is currently the setup of choice: CMH lamp is used for vegetative and floral growth, however for cannabis application, HPS is used after initiation of good flowering buds; we do this because CMH still cannot match the photon and the plant lumen output of HPS with a very lush plant like cannabis. Only use HPS is you are expecting jungle-like growth conditions, and only in the established flowering phase.