The honest part about MP3 → WAV
Converting to WAV doesn't restore quality MP3 compression removed — no converter can, and any site implying otherwise is lying. What it does is make the audio editable and universally compatible: WAV is uncompressed, so editors can cut it without generational loss, samplers can load it, and picky hardware accepts it. Expect files ~10× larger; that's what uncompressed means.
FAQ
What's the output spec?
16-bit PCM at the source's sample rate (usually 44.1 kHz), stereo preserved — the standard everything accepts.
Can I convert WAV back to MP3?
Yes — drop a WAV on the MP3 converter. It takes any audio format.