I was very impressed with the materials and quality of this pump when I opened the box. I can say if it was leak proof when I first opened it since the first thing I did was take it apart and dope and tape all the fittings. Upon doing so, I did a pressure test using the supplied adapter for the purpose. Everything checked out. I had to purchase a separate adapter for use with the fill probe on my Hatsan flash since none of the supplied ones would fit the probe. With the proper adapter, the pump works well and easily fills my rifle to 200bar.