In 1971, Jensen received a number of wax samples for testing from Martin Matsbo, graded as ”interesting”, ”somewhat interesting” and “very interesting”.

One day it was sleeting in Lillehammer and Jensen seized the opportunity to get out and test some new ski wax mixtures. The weather was perfect for testing wax in difficult snow conditions. So he did the usual, waxed each ski with different waxes and headed off up into the forest. The skiing was slow-going and slippery, and he had to stop plenty of times to apply the 20-30 waxes he brought with him, and had to scrape each one off before applying the next.

One of the samples labelled “somewhat interesting” glided extremely well, while also providing excellent grip on the half-dry snow. Jensen had never experienced anything like it under similar conditions. He travelled straight home and called Matsbo:

“We found it,” he exclaimed as if he had found the elixir of youth. A recipe called K-779 was given the name “Blue Extra”. On the right snow conditions and properly applied it ensured good gliding properties and good grip. The wax became a classic. Swix has sold millions of boxes of Blue Extra.

During a time when cross-country skiing became very trendy in a number of countries, Swix regained its leading market position, also among elite skiers.