106 is a blue from the Au Ver à Soie 1 fil Hi Lustre range: a 1-ply Hi Lustre, extra bright metallic thread. On its own or combined with another thread, for example threaded through the same needle as strands of silk or stranded cotton, it adds bright highlights to embroidery on any fabric or canvas.
1 fil Hi Lustre comes in around 25 colours in gold, silver, copper, plain shades and blends; the "bouclé" version comes in around 45 colours. Photographs are only a guide: the sheen of metallic threads changes a lot with the light.