That ESC is a replacement for the Volentex range of RTR (ready to run) boats and has two battery connections for batteries in parallel - is that what you wanted? Those type of boats are tight for space and to give good speed and duration they utilise two batteries.
Also that ESC has to be water-cooled as it is wrapped in plastic and doesn't have any cooling fins.
I've got a HobbyWing Seaking ESC which has cooling fins as well as water connections so should be alright without water-cooling though I'm going to change to HobbyWing car ESCs for other builds.
My Huntress at 23" doesn't have water-cooling and is fine but is run at varying speeds. My RTR race boats are fitted with ESCs like the one you have bought and are obviously run at constant high speed.