Pentatonix consists of lead vocalists Scott Hoying (22), Kirstie Maldonado (21) and Mitch Grassi (21), vocal bass Avi Kaplan (25) and beat boxer Kevin "K.O." Olusola (25). Their most recent album PTX Volume 2 debuted at #10 on Billboard's Top 200 Album Chart and features 3 original songs and 7 covers including a song Daft Punk medley for which the video has garnered over 65 million views. Since their debut in 2011, the quintet has released 3 albums (PTX Volume 1, PTXmas and PTX Volume 2) selling over 500,000 copies combined. Online, the Pentatonix YouTube channel boasts well over 445 million views with more than 5.6 million subscribers, is the #61 most subscribed-to channel and #16 most subscribed-to music channel.