Iris Diaphragms provide continuously variable apertures for a multitude of optical applications, such as beam alignment, light attenuation, or as baffles to block spurious reflections and scattered light. Three models are available with aperture size ranges of 1.0 mm to 11 mm, 1.5 mm to 25 mm, and 2.4 mm to 41.3 mm. Model ID-1.0 and ID-1.5 Irises mount directly to optical posts and pillars with an 8-32 threaded hole or M4 threaded hole for metric versions. The miniature ID-0.5 Iris mounts to posts, such as SP series posts, with the MH-2P Optic Holders.

For smooth adjustment and an optimal shape for the aperture opening, each iris consists of an array of curved, overlapping, spring-steel leaves that intersect into the circular opening. Up to 18 leaves adjust continuously between two supporting rings with the adjustment of a pin handle attached to the inner ring.