**********Spare parts contains 12 prepared slides of various specimens including plants, insects, and animal tissues. *****Spare parts contains 20 stickers. They are tiny and ultra sticky, every piece can be used for around 10-20 times. The sticker will be delivered together with the slides. *****The bilateral sticker is used for connecting with the cell phone camera lens. When you use the sticker, use something sharp to dig up the small middle part of it, then peel off the paper of one side, stick it to the lens.