The ROOLOX Barbell Collar works by using a small amount of initial friction to engage the bar. The grip force is then multiplied as pressure is applied. It is important that your barbell is free from oil and grease before use. Most new barbells come with a light coating of oil which can be easily removed by wiping the bar surface with alcohol applied to a soft cloth. Periodically clean both the barbell and the rubber pads on the ROOLOX collar to maintain best grip.