For 3k, this is the best option.

thank you

what for is a prop saver used?

Prop savers are used to attach prop to the motor shaft. The advantage of this over others is that, in a nose dive crash, the rubber band allows the prop to move and absorb the impact of the crash, thereby saving the prop.

9 ch is also good but a bit expensive i guess...

configuration for blue baby 42 inch