ACT is a lossy ADPCM 8 kbit/s compressed audio format recorded by most Chinese MP3 and MP4 players with a recording function, and voice recorders. Many models of recorder that use the ACT format do so only for their lowest-quality recording setting; if the quality setting is increased then a different format, typically WAV, is used, creating much larger files. There are different versions of ACT; files produced by later devices could not as of June 2009 be read by any free standard audio player and converter software, only by the supplied MP3 utilities.