(under subclass 120) Structures in which each insulating layer consists of nonimpregnated fibrous or fabric material as defined in note (1) of subclass 121.
(1) Note. Where any one of such layers is impregnated, the patent will be placed in this class, subclass 121.
(2) Note. For single, nonimpregnated, fibrous or fabric layers, see this class, subclass 124.
(3) Note. All patents having claims to two or more contiguous nonimpregnated, fibrous or fabric layers are to be cross-referenced here.