Amazing tool. Really helps with setting those pesky nails. I used to use a set of nails and it was hard work; I often slipped and made a big hole in the wood next to a nail. I first used them in a red oak finish and hammered in nails with a nail gun that didn't go all the way in. I was amazed at their power and strength pounding nails. Be careful though, you really need to use a lot of force to hold one piece against the nail while pulling the other back. This can be difficult for some people who have difficulties staying on land due to a disability. I loosened my grip several times and he loosened and slid sideways when I released him. My advice: Practice first if your results are critical. The photos of people in other reviews with damaged feathers must be because people don't know what they are doing because the feathers are stuck. Any spring deforms when overloaded.