Polycrystalline diamond consisting of grain sizes from several nanometers to several micrometers can be grown. Most microcapsules have pores with diameters between a few micrometers and a few millimeters. These holes are called "micro vias" and can have diameters as small as 10 micrometers. Human macrophages are about 21 micrometers in diameter. Wool varies in diameter from below 17 micrometers to over 35 micrometers. The particles are typically of a diameter in the order of 10 to 100 micrometers. The blue detector is sensitive to wavelengths of 9.3 micrometers. Laser cutters have positioning accuracy of 10 micrometers and repeatability of 5 micrometers. Each pixel is 78 micrometers in width. The HEPA specification requires removal of at least 99.97% of 0.3 micrometers airborne pollutants. The glower operates best in wavelengths from 2 to 14 micrometers. PCB tracks can have a width of just 10 micrometers. The layers of tissue removed are tens of micrometers thick. Glass solders are available as frit powder with grain size below 60 micrometers. Diatoms are 2 to 200 micrometers in length.