Those kokedama are made with Hypnum plumaeforme Wils. Moss. They are dry but live. The kokedama moss ball will regreen. 

Purpose: it is stylish planter for small plants, like various fer,m mini rose,  saxifrage, small bonsai tree, orchid, etc. You can hang them or place them in a bowl, or dish as my photos show. 

Hypnum plumaeforme Wils. Moss  is a compararive long moss. It suits for open terrarium. It will keep green for years and you are expected to have a green moss ball after weeks. 

How to use it: sink it in water till it is total moist, put in soil and plant via the hole (or plant nothing if you like moss only). Then hang it or place it in a bowl / dish.

How to water it: sink it in water for 5-10 minutes every several 2-3 days (when the moss ball becomes light and dry). 

Size: 

kokedama ball diameter: 

6cm / 2.4 inches
9cm / 3.5 inches
12cm / 4.7 inches
15 cm / 5.9 inches

What you will get: 3 units of kokedama ball the size you choose, plants are not included.