Kinetic Systems Inc. has introduced a line of burr-free microholes and holders for use with optical systems. The PA Series pinhole apertures offer 1 to 1000-µm-diameter pinholes, and the HPPA Series apertures feature a 0.0005-in. substrate material. Both are supplied with reusable, dustproof packages. Also available are the Series AS air slits in widths from 5 to 500 µm; the AH Series aperture holders, which accommodate 3/8-in.-diameter discs with retainers; and the Series OS optical slits in widths from 10 to 500 µm.