Signwriting Mouth Open Rectangle Wrinkled (U+1DA4B) is a Unicode nonspacing mark from the Sutton SignWriting block. It resides on Plane 1 (SMP, Supplementary Multilingual Plane), has bidirectional class NSM (nonspacing mark), is not mirrored, and has combining class 0 (Not Reordered). In HTML it can be written as 𝩋 or 𝩋. Because it is outside the Basic Multilingual Plane, proper font support is required; otherwise a fallback box may be shown.