thanks Rickie , i did read those instructions , i plugged in the unit +the black box + transducer in a barrel of water , after manual settings it shows SI and DI screens ! i will install it on boat since it works i think , one thing : i did see an option somewhere in menus that asked if it is an MEGA or not transducer and after trying many times could not access that menu again , that showed me that it was an option .