HOBBYHOT8482; HOBBY HOT 75mm RED Aluminium Cooling Ship Rudder for RC Ship HR280 with Android Apps Special Bundle High quality CNC aluminum rudder with water pickup is designed for small electric rc boat. This CNC rudder with water pickup can be installed with your water cooling ESC and water cooling brushless motor jacket. It makesmore efficient for cooling. Specification Blade length: 75mm (2 15/16 inches) From end to rear edge of the rudder blade: 61mm (2 3/8 inches)