Listen to Knock Em off (feat. Chuck Wester, Zelly Mac, Verse & Mr. Birch) online. Knock Em off (feat. Chuck Wester, Zelly Mac, Verse & Mr. Birch) is an English language song and is sung by O-Zone. Knock Em off (feat. Chuck Wester, Zelly Mac, Verse & Mr. Birch), from the album The Lost Tapes (Deluxe Edition), was released in the year 2013. The duration of the song is 3:36. Download English songs online from JioSaavn.