It originated, as the name suggests, with the advent of the OK classes in 2016. A compact, lighter radiator was needed that would marry the philosophy of the OK/OKJ classes, namely simplification in order to reduce the weight and costs of karts. New Line's response to this requirement is called R-OK.

With the arrival of the OK classes, the total weight of a kart plus driver has been reduced compared to previous KF classes. That is the reason New-Line Racing also wanted to contribute by producing the R-OK, a radiator capable of meeting the cooling needs of the new CIK-FIA approved non-shifter karts, while keeping the weight of the cooling system to a minimum. To do so, compared to a regular R , a "light" support was developed and produced that allows the radiator to be adjusted/tilted in any position in all situations.

While RS, model might represent the ideal radiator for KF classes, the ideal choice for the OK class is the new R-OK model. This also has a positive effect on the economic front, since the list price of the R-OK is lower than the RS. Not only that, but New Line, to continue trying to minimize the costs for kart drivers, has chosen to also equip the R-OK model with an air shield curtain as standard, thereby offering a special price for the "radiator + curtain" combination.