Optim Ultrafine White Merino. Strong and Lustrous! This newly developed fiber is merino wool that has been stretched in a special process that preserves the luster and strength. The results are a longer (5-7 inch staple) and finer (12-14 microns) ultrafine merino wool that is softer and lighter than most cashmere. Most suited for needle felting, blending, or spinning. Treat yourself to this ultra luxurious fiber, you'll be hooked!