Glover, we have used a pair of clamps for 40 years. We clamp the calves at around 450-500 lbs so they get the growth. It takes 60 days for the testicle swelling to go down and they can be sold as steers. We "clamp" close to 200 per year and I dont ever remember missing one. It is very simple to find the cord and clamp one side, hold 2 seconds and release and find the other cord and clamp it. There is no blood at all, however it takes longer than either the knife or banding before they sell as steers. If I am going to sell within 60 days, I band them. I only knife them if I just have one or two in a big pasture and dart them to tranquilize them and then knife them---no bleeding if done when they are asleep