... can replace the common 250 HPS street lamp .2.Small size ,low weightSeparate electronic ballast ,less than half size ... Excellet light efficacyExcellent ratio for the discharge tube diameter with the lenth (A.R.),stable light output .New PGZ12 bulb clamp head ... .peak voltage protection ,protect the light source;anti-surge current,protect the electronic ballastHigh working efficacy system ,-power factor ...