Abu'l muzaffar mahmud shah khalji duriba bi-hadrat shadiabad // al-khalifa amir al-muminin khulidat khalifarahu and date 848 (= 1444 CE). 21mm, 8.54 grams. Hadrat Shadiabad mint. G/G #M36. 

High-silver billon tanka, excellent quality. Much scarcer than Goron/Goenka indicated.