This filter paper fits nicely into the Wave series dripper by Kalita. It fits into the Origami Dripper as well! 

The muffin/cup-cake shape like filter paper gives a larger brewing surface area which allows for more even extraction. 

155 FP (155 Kalita/Size S)
Recommended dosage: 10-18g

185 FP (185 Kalita/Size M)
Recommended dosage: 15-30g

Dripper that uses this filter paper:
Origami dripper
Kalita glass wave dripper
Kalita glass wave dripper (wooden holder)
Tsubame stainless steel wave dripper
Tsubame copper wave dripper