M4R or iPhone Ringtone is the format of ringtones for mobile devices from Apple. This is the same format as M4A but with it has several limitations. The duration of the audio stream should not exceed 40 seconds. In case the duration is longer, iTunes does not install the ringtone on the mobile device.
WAV is a container format for storing a record of a digitized audio stream without any compression. This format was developed by IBM and Microsoft in 1991 and was used in all versions of Windows. As the format uses audio streams without any compression, the files become very large in this format.