It supports wireless earpieces and headphones through the HSP profile. The built-in Bluetooth v2.1 supports wireless earpieces and headphones through the HSP profile. Radios are carried and used with earpieces & microphones on duty. The built-in Bluetooth v3 supports wireless earpieces and headphones through the HSP profile. The built-in Bluetooth 2.x+EDR supports wireless earpieces and headphones, which requires the HSP profile. The earpieces are able to utilize the pressure from the headphone itself to inflate itself. Accessories can include built-in radio microphone and earpieces. To improve these aspects for ear-EEG, nanostructured electrodes and soft earpieces have been proposed. One remaining use for crystal earpieces is in crystal radios. They wear white suits, black gloves, earpieces and black sunglasses as their primary uniform. Attempts at creating in-ear generic earpieces are also known to be under way. George "Rose" Barclay began to use straps and earpieces to protect his ears. Presently, referees wear wireless earpieces, to allow backstage officials to communicate with them during matches. The actors wore wireless earpieces on set so they could sing to accompanying piano music. The musicians wore earpieces to hear the playback.