Q: How is it to pray with a Bluetooth piece attached to the ear?
A. Salaah is a worship which requires maximum concentration and devotion. A person cuts himself off from all worldly attachments when performing Salaah. Although Salaah with the earpiece is valid, it is best to remove it so that you and others around you are not distracted.
Allah Ta'aala knows best.
Moulana Yusuf Laher