@bigdaddy_771512482971796 I just received my M521 doorbell from Aliexpress and can confirm that it DOES pair with the Reolink doorbell. No instructions with it but there are instructions on the internet. Mine came with an EU plug as I don't think they have one with an Australian plug but adaptors are available. It has 3 volumes, right up to very loud, 57 melodies and will pair with more than one button. They seem to have different prices but I paid around AUD $6.50 delivered to Australia in about 2 weeks.
