Feature●Professional Digital Echo with Separate Stereo/Mono Hi / Low / Repeat and Delay Controls●USB Recording Function *Sing and Record Your Voice at the Same Time*●Model: 2023 Bluetooth Function send/receive from any device (Iphone, Ipad, Android, Youtube, Karaoke Apps)●4K HDMI Input●Model: 2023 Optical / Coax Audio Input (Connect directly from any Smart TV for Youtube Karaoke)Description Newest Model This Singtronic KA-550Pro Professional 1500W AV Karaoke Mixing Amplifier built in Optical, Voice Record, HDMI