Nikon's Action Extreme series offer lots of features that will be appreciated by those who enjoy the view provided by classically-styled porro prism units. Following the enormously popular Action series, Nikon has made significant improvements. The group still retains the high-refraction prisms with their wide viewing fields, and every model has a tripod adapter threading for easy extended glassing from a stationary position. The 10x50 model, with its broad 5mm exit pupil, is ideally suited to high powered lowlight observations. Their performance in twilight is commendable.