I bought these because I wanted a clip that was a certain size. But they are very difficult to open. The spring spool is too thick and about 3 wraps compared to another brand I like that uses a slightly thinner spool that is about 4 wraps. Both clamp well and I don't understand why this brand had to use such a thick spool of wire for this medium sized clamp. The only reason I didn't repurchase another brand is because they only came in different sizes and I didn't need all sizes.