Best dye for polyester?

[MadameSapphire]

Just that really. Have a few items of clothes to dye and am not really sure where to start re. dying polyester! Thank you x

There is an American product called Fit that I think works on polyester.
Dylon won't.

*Rit not Fit

Thanks @thedevilinablackdress - will search out Rit x