This DJ from Canada always plays without headphones and despite that his transitions are on point.
In case you're not familiar what headphones do:
-you can hear the next song before playing it out loud
-they tell you how to queue the next song smoothly
-a dj uses it to beat match both tracks together and in some cases key match as well
Not wearing headphones increases the difficulty to beat match one track into another but in order to achieve a perfect blend the DJ must know his music very very well.
You can follow him on Snapchat and Instagram: kingofmontreal