Power Supply difference between two prong and three prong

by Gilbert
(Puerto Rico)

My Turbo T-Jet motor died yesterday. I google ebay to find another Turbo T-Jet and find an aquabot Ecojet without power supply. My old Turbo T-Jet has three prong cable and the new EcoJet has two prong cable. What is the difference? EcoJet will work with this power supply.