This item is known in the catalogues as one of the following numbers:
Michel: 17 A (rose, perforation 14½:14) or 17 D (rose, perforation 15);
Yvert & Tellier: 20 (rose, perforation 14½:14 or 15);
Stanley Gibbons: 32 (carmine, thin paper, perforation 14½:14) or 37 (rose, thick paper, perforation 15);
OBP: 20 pale rose or 20a carmine-rose or 20b carmine (line perforation 14½:14) or 20A pale rose or 20Aa carmine-rose (comb-perforation 15).