The Kalita Wave poruover feature a flat-bottomed brew bed and a filter paper that ensures minimal contact of the coffee and the wall. It's a great brewer and one that allows for larger brews than smaller conical shaped pourovers. 
 
Uses Kalita 185F Filter Papers 
 
Specs.
Use Kalita Wave Filters 185
Material: Heat resistant glass
Dishwasher safe
#185: Diameter 10.5cm x Height 8.3cm
Weight: 116g
Made in Japan