Sony sbh24.

A tiny, basic but decent bluetooth receiver which includes their mh750 earphones. I often recommend this over any cheap wireless buds because of the simplicity of the design and ability to use any earphones if the included pair are damaged. I bought mine in UK for £24 last year and didn't expect much but was pleasantly surprised. It can be bought for as little as €16. The earphones have a bassy, warmish neutral sound.