The JSF is designed to be international and to be reasonably easy to customise to national requirements. Eight countries were involved from the beginning, Australia, Canada, Denmark, Italy, the Netherlands, Norway Turkey and the United Kingdom, and invested in the development of the JSF in return for participation in R&D. Other countries such as Israel decided to acquire the JSF through the military sales process. The article notes that the JSF has also proven to have significant diplomatic leverage, e.g., the opening of relations between Israel and the UAE. The JSF is also beginning to demonstrate its military worth. The article notes that 'In recent exercises, U.S. F-35s achieved kill ratios in air-to-air combat of 15 to 1'. The JSF also has a well-developed strike ability employing stealth, manoeuvres, electronic warfare, and smart weapons to penetrate a potential enemy's defence. Further, the aircraft is easily customised and can be periodically upgraded to improve its capability.