Paper Filters:

Filters are necessary to remove the fine particles which can negatively impact the flavor and make the appearance cloudy. White, oxidized filters work the best as they do not impact the flavor like natural (e.g. hemp, bamboo) filters can. An important tip is to always wet the filters prior to adding the coffee as this helps ensure the proper flow.

Scale:

Since coffee can have different density, measuring by volume is not as accurate as measuring by weight. Aficionados will even measure the water by weight rather than by volume since it will give the most precise measurement.

Thermometer / Timer:

Since temperature and time are important factors of extraction, it makes sense to be as precise as possible for these measurements.