The object of this paper is to compare the actual moisture content of wool, referred to as the true regain, with the commercial regain as determined by an ordinary conditioning oven or by the Bradford Conditioning House (B.C.H.). It is found that the commercial regain as determined by the B.C.H. is about % low compared with the true regain (e.g., 15 % instead of 16%). The Conditioning House uses a type of oven in which the air is preheated and forced through the wool at a temperature of 235–240° F. On the other hand the ordinary commercial gas and electric ovens tested gave a still lower figure, viz., about 1% low (e.g., 15% instead of 16%). It is shown that unless the air be dried by special means the B.C.H. commercial regain is as near the true regain as practicable, and is therefore satisfactory as a commercial standard but the smaller installations in mill use are less perfect. Many ovens are installed near sheds near scouring or finishing plants, or places where gas is burnt, and the air may contain a considerable amount of moisture. It is suggested that those who use their ovens regularly should compare their figures with those of the B.C.H. at frequent intervals so that they may know what correction to apply.