Secure Grip: Simply press the latch down to snap the lock collar clips shut. Use the adjustable knob to create a bit more tension as needed to ensure a safe workout Construction: Made of durable Nylon resin, the Marcy Olympic Lock Collar Clips are built to last and are lightweight at 8 oz per pair. Fits Olympic Bars: The Marcy Olympic Lock Collar Clips are made to fit Olympic bars. Use the tension control knob to add a bit more pressure as needed for a safe workout. And, the pressure pads ensure the bar is gripped tight, while also conforming to the Olympic Bar. Easy to take to the Gym: Don't hesitate to take your Marcy Olympic Lock Collar Clips to the gym or to any place you workout for a safe and secure workout Multiple Colors: Marcy creates the Marcy Olympic Lock Collars in Blue, Red, and Black.