The Gabi Master A is a complete pour-over brewer: a small flat-bottom filter cup sits below a water reservoir and perforated dispersion screen. Pour into the reservoir and gravity meters the water into gentle droplets across the coffee bed. It needs no power or separate dripper. The Master B uses a similar idea as an accessory placed over another brewer; it is not the filter cup shown here.
The manufacturer pairs the Master A with Wave 155 paper, shared with the Kalita Wave 155. That paper compatibility does not make their recipes interchangeable: the Gabi's reservoir sets the water delivery, while a Kalita recipe assumes a person controls the stream. Water cools while it waits in the reservoir, so kettle temperature and preheating matter. Start with a small dose and let the reservoir drain before adding more water rather than filling it past the rim.