ARTISAN ZERO ISSHIKI (Type-1) Premium mouse feet [Made in Japan] Donuts shape Outside diameter:8mm / Inside diameter:3mm / Thickness:0.5mm Include: 8pcs (4pcs/mouse x 2sets) To improve a stopping quality. Donut shape feet causes increase the sink and affects friction control. Best performance with ARTISAN mouse pads HAYATE/SHIDEN/SHIDEN-KAI series.