It is a novelty instrument made of tubes between 1 and 8 meters long, arranged in a circle. The person who sings to the nelofon stands in the center of the circle and strikes the ends of the tubes. Each tube produces a different sound, depending on its length.

You can find information about this instrument here: http://www.radiocluj.ro/2018/07/31/7-instrumente-muzicale-ciudate-de-care-nu-ati-mai-auzit/