I have tested this Inlet end of March in a down sleeping bag, slept very well and not frozen. The specified 14 ° to the the Inlet to expand the temperature range of the sleeping bag, but I think rather a laboratory value. Of course it warms very clearly, especially when one compares it with the otherwise common silk Inlets. But the 14 ° I would rather reduce significantly and rather speak of 5-8 °.
Nevertheless, I can recommend the Inlet, not least because of the high quality impression.