Phonak Hearing Systems pass through different development and study stages. At an early stage, feasibility studies are conducted to investigate new algorithms, features and functions in an isolated manner. If the benefit is proven, their performance is then investigated regarding interdependency between all available algorithms, features and functions running in parallel in a hearing aid (pivotal/pre-validation studies) and, as a result, they get optimized. Afterwards, and prior to product launch, the Phonak Hearing Systems undergo a final quality control in terms of clinical trials. This is a pre-validation study, investigating optimized algorithms, features, functions and wearing comfort. This will be a clinical evaluation which will be conducted mono centric at Sonova AG Headquarters based in Stäfa (Switzerland).

Inclusion Criteria:

• Adult hearing impaired persons (minimum age: 18 years) with or without experience with hearing aids
• Good written and spoken (Swiss) German language skills
• Healthy outer ear
• Ability to fill in a questionnaire (p/eCRF) conscientiously
• willingness to wear custom made Hearing aids
• Informed Consent as documented by signature
• Benefit with TFG tool at least on one ear

Exclusion Criteria:

• Contraindications to the MD in this study, e.g. known hypersensitivity or allergy to the investigational product
• Limited mobility and not in the position to attend weekly appointments in Stäfa (Switzerland)
• Limited ability to describe listening impressions/experiences and the use of the hearing aid
• Inability to produce a reliable hearing test result
• Limited dexterity (not able to change a 10size Hearing aid battery)
• no Benefit of the TFG tool on both ears
• Known psychological problems
• Central hearing disorders