Pro:1. Very difficult. I was surprised by the weight of the package.2. Not skinny. These don't bend at all. You don't have to worry about a bent collar anymore. Cons: 1. I'm not sure if it's stainless steel. It looks like a cheaper metal alloy. I really hope this product is lead free. It almost looks like the coating is painted. Not what I expected from stainless steel.2. The edges of the collar remain uneven. They are jagged. Not sharp in the sense that it will snag on shirt but has many imperfections/dimples.3. I'll update this as I use them more, but given the weight and ease of sliding, I would be concerned about them slipping out of the collar with normal wear. Not tested yet but there should be some friction on the chainstays to prevent slipping. For the price I think the product is fair. but they need to smooth the edges and the metal needs to be of higher quality.