A card on local sweet of Suzhou known as Song Zi Tang (松子糖). Due to its shape, it is also known as dumpling sweet (粽子糖). Thanks Alice Ye.
A 3 Yuan personalized stamp and a 1.50 Yuan watermelon stamp (2016-18, 4-3) were used. They were cancelled in Jiangsu Suzhou Baitaxilu 1 (江苏 苏州 白塔西路 1) on 17.4.2017.