What is it? OSO Barbell Collars are made with aircraft grade aluminum. They have a rubber inner liner and an extra hinge to open further than 90 degrees on the release lever which allows for easier placement onto the barbell. When clamped down, THESE THINGS DO NOT MOVE (which is what you want in a collar).
What do I think? I have never seen in any way, shape, or form, a barbell clamp that works better than the OSO collars. Admittedly, I have not tried a ton of barbell clamp products, but these work better than any of the ones I have ever seen or used.
Why do you need it? If you like to clamp your weights securely onto your barbell and have them not move while you finish a workout or lifting session, these are the collars you need. I couldn’t imagine opening a gym or affiliate without having these as part of my equipment.
When should you use it? Honestly, any time you put weights onto a barbell, use these collars. Especially for Olympic lifters, but any lift would benefit from this product.
How do you get it? OSO has their own site and they can be purchased in a variety of colors and even are customizable now. You can pick up a pair for $49.95.