Dumbbell Bar Weight Lifting - SODIAL(R) 14" Chrome Dumbbell Bar Weight Lifting 4 Vinyl Spinlock Collar 2.5cm It also includes rubber grip handles for comfort and stability. Spinlock Collars are made from robust and high grade heavy duty vinyl. Four Spinlock collars also included with bars to hold weight plates in place when lifting. Spinlock collars are easy and quick way to swap plates. Ideal for various Arms, Chest, Shoulder, Abdominal, Legs or Back workouts.