Instant purchase available. These are dot skates from ESPTIGER. Each pack contains 10 dots each of 5.5, 6.0, 6.5, and 8.0 (mm) sizes (40 total). As they are consumables, the advantage is that they are inexpensive and can be replaced frequently. If you use a hard-type mousepad, such as a glass mousepad, the skates will wear down quickly, greatly affecting the feel. Therefore, it is recommended to buy inexpensive ones in bulk and replace them about once every 1-3 months. They are also recommended for those who, like me, buy multiple mice and just want to change the included skates to dot skates because they don't like the included ones.