The Aquastar 240A HV Water cooled ESC is a high quality ESC designed from the outset for serious boat racing.
It is a microprocessor controlled, high voltage, ultra-low resistance (0.75m?) Opto speed controller for 4 to 12s LiPoly batteries (up to 38 cells NiMH/NiCad) and uses 8 AWG wires (min 8mm connectors required) for maximum operating efficiency.
A unique feature of the Aquastar 240A is the integrated cooling plate between the MOSFET boards. When coupled with the dual cooling inlet/outlets this keeps the ESC cool under the most demanding loads.
This ESC has 8 programming options for flexibility, on-board data logging, 300A surge capacity, adjustable switching rate and many more class leading features. 
Programing can be done with your transmitter, programming card or optional USB adapter 

Features:
• Microprocessor controlled
• Extremely low resistance
• 240A continuous (300A surge)
• Up to 38cells NiMH/NiCad or 4~12 cell LiPoly
• High rate adjustable switching (PWM: 8 KHz, 12 KHz, and 16 KHz)
• Optically coupled - separate battery pack required for radio
• Programmable low voltage cut-off, cut-off type, brake type & start-up
• Programmable timing (Auto recommended)
• Firmware Upgradeable
• Thermal cut-off (100°C)
• Safe arming program ensures motor will not start unintentionally.
• Auto shut down when signal is lost or radio severe interference is experienced for more than 3 seconds.

Specs:
Constant Current: 240A
Burst Current: 300A
Voltage: 14~51v (4~12S LiPoly/Up to 38 cells NiMH/NiCad)
Wire size: 8AWG
Size: 135mm X 57mm X 23mm
Weight: 220g