In 2012, the National Institute of Occupational Safety and Health (NIOSH) developed an insert-type hearing protector fit-testing computer program called HPD WellFit. The program was and is very successful, and it won the 2013 NIOSH Bullard-Sherwood Research-to-Practice Award. Michael & Associates licensed HPD WellFit from the CDC in 2013 and spent a year with the NIOSH programmer modifying it for use in general industry. The result of this work is FitCheck Solo. More than 200 copies of FitCheck Solo have been sold to the military and general industry. FitCheck Solo is intuitive and easy to use and it has been very popular with users as tens-of-thousands of hearing protector fit-tests have been performed. This proposal involves developing an Android Tablet-based version of FitCheck Solo. The Android system will be cost-effective and portable and will include important and innovative additional features, including single-subject F-MIRE hearing protector measurements, real-time analyzer octave band measurements of noise exposures and a complete audiometer function. Additionally, the FitCheck headphones that have been in use for many years will be updated for maximum ambient noise reduction and improved comfort. While the FitCheck Solo program will be scalable and will perform attenuation measurements on all types of insert hearing protectors, the F-MIRE capability will allow this instrument to measure hearing protector attenuation on all other types of hearing protectors, including earmuffs, helmets and double protection.