Oskar Karlsson was born in 1914 in Sjöarp outside Gnosjö. He had a great interest in animal and nature and spent a lot of time in the forests of Småland. He collected butterflies and was able to art the preparation.
During his military introductory month in Karlskrona he saw a stag beetle he brought home to the foundry where he worked. With this insect as inspiration, the boot jack came into being which is still manufactured by Essem Design.