Is it ok to have both ECE r 44 04 and i-Size product in my car?

As long as ECE R44 04 is allowed by National legislation you can use both ECE r 44 04 and i-size products in your car. This will be at least till 2017. ECE r44 04 products with isofix do have a car list to explain in which vehicle (seat position) the child safety seat can be used.