looking for specific plugin…

Hi- i found a plugin a while ago that will allow me to send emails to my registered users in “spurts” so i don’t get banned from my hosting provider, as they don’t allow emails to go out to 500+ users at once…it has to be spread out… i can’t remember the name of the plugin and i’ve been searching and cannot seem to find it. does anyone know what the name of this plugin is??? i really need it.

thank you.