The name NoordWest (i.e. Northwest) refers to the duo's musical repertoire and, coincidentally, also to where in the Netherlands they lived when the duo was founded: Els lives in Leeuwarden in the north, Thomas (used to live) in Leiden in the west.
Both play as folk musicians in several quite different groups. As Duo NoordWest they have, over the past 25 years or so, built up a vast repertoire of dance and listening music from Scandinavia, with an emphasis on Swedish music.

In several hundreds of sets and arrangements of traditional melodies they combine a range of authentic instruments: violin, härjedalspipa and seljefløjta / sälgflöjt (Scandinavian shepherd flutes), nyckelharpa and dalasäckpipa (Swedish bagpipes), diatonic accordeon (melodeon) with concertina, chromatic accordeon, various recorders and even a baroque trombone.
Their aim is to play the music the traditional way as well as combining other styles, thus giving full credit to the music's nature of a living tradition.
They always play "without dots" and prefer to play without amplification for better contact with the audience and/or dancers.

They both travel to Scandinavia regularly to collect and learn more tunes, dances and styles, to gather more background information and to meet musicians and luthiers.
They play for (mostly Scandinavian) weddings, for dance events, in small theaters with a program of music and folk stories, at midsummer and midwinter events, ('Scandi') fairs and markets, etc.
They also play for Lillan, an Amsterdam based Swedish dance group that does dance performances and organises informal Swedish dance evenings.

Over the last few years Duo NoordWest gave a lot of workshops Swedish dance for beginners and intermediate level: in the Friesland region at first but now in many places in the Netherlands. A daytime workshop is usually complemented with a Swedish dance evening (often combined with 'Balfolk') to bring the newly learned dances into practice.