This is a great exercise to isolate the biceps and switch it up for maximum gains! In this video I'm using a Hammer Strength row machine, but if this is not available in your gym you can use an incline bench.
Keep your elbows in as you perform this and contract the bicep until your arms are fully flexed. Lower all the way down and repeat.
Variations: I am using an EZ Bar in this exercise, but you can use dumbbells or even cables as well.