The accessory to help to strain loose leaf tea or herbs. Simply hold the strainer over the cup as the tea is poured from a teapot. It could fit opening of some cups or teapots. In that case it could be use as infuser. 

Approximate dimensions: 10 cm L (including handle) x 6.4 cm W x 6.4 cm H (4 inch L x 2.5 inch W x 2.5 inch H)