WAV files are about ten times larger than an MP3 of the same recording. WavPack shrinks audio without losing any of it. WAV is at home in recording, editing and mastering; WV is the usual choice for archiving CDs and recordings without losing anything.
The defaults suit most files. Under Options you can trim the start and end.
This pair uses the compatibility engine, ffmpeg built for the browser, because WV cannot be written by the browser's built-in codecs. It is a one-off download of about 10 MB that the browser keeps, it is slower than the built-in codecs, and it takes files up to 1 GB.