Apollo propellers are highly polished, ultimate performance stainless steel wheels. Apollo is designed to use Michigan Wheel’s XHS hub system and is interchangeable with the Mercury Flo-Torq II hub system. If you chose a hub kit, either the XHS or Flo Torq II will be supplied. The 993044 is a standard diameter right hand 3 blade, which is good for 150-200 hp motors on all types of boats. FREE SHIPPING! If you’re not sure what hub kit you need–please call or email for help.