The Sony recorders ICD-PX312, ICD-AX412 and ICD-UX512 use AAA batteries and have a microSDHC card slot. These only support files up to 192kbps, but do support variable bitrate files. The PX312 has a mono mic, while the others have a stereo mic. I don’t know how well these recorders work as players. I assume there is no tag browsing, only browsing by folders.