Olympus 300mm F4 IS Pro is an Auto Focus (AF) Telephoto Prime lens with FourThirds max sensor coverage. When mounted on a FourThirds sensor camera, it will give you an FF equivalent focal range of 600mm. With a max aperture of f4 at 300mm, this is a moderately fast lens.
This lens features on optical image stabilization which helps capturing sharper images at lower shutter speeds. Olympus 300mm F4 IS Pro is weather sealed which makes it an ideal lens for outdoor use, especially when coupled with a weather sealed camera body.