The Sekonic Speedmaster L-858D-U Light Meter is a versatile and high-quality tool designed for photographers and videographers. With a shutter speed range of 1/3-stop increments to 30 minutes, light reading method of incident and reflected light, and exposure memory for 9 readings, this meter provides precise and accurate measurements. Its measuring modes include aperture priority, flash duration analysis, and high-speed sync flash, with a luminance range of 0.3 to 290,000 fL and 0.1 to 980,000 cd/m². The meter is cordless, has adjustable spherical to flat diffuser, and operates on 2 AA batteries, making it convenient and portable for on-the-go use.