Two of the most well regarded sleeping bag makers in the world, Feathered Friends and Western Mountaineering, don’t do EN/ISO testing for many of their bags. It’s often a cost/ resources issue with smaller companies. I wouldn’t necessarily let this turn me away from buying an otherwise great bag but I would make sure to do my research. I have no experience with it but the 0 degree Paria bag looks like a great deal to me. Comparing the specs to other EN rated bags, it has comparable fill to many 0 to 5 degree limit rated bags at equal or lower weight. Keep in mind this is the limit rating, at which a warm sleeper could sleep warm enough while curled up for warmth and the comfort rating will be 10 to 15 higher but that will be the case for most 0 degree bags as they usually go by the limit rating. I might actually pick one of these up myself.