Sight Base Extensions provide the ability to increase the distance between the rear and fore-sights. This can reduce the impact of aiming errors, and allows many older shooters to have an improved sight picture.

For smallbore rifles there are no regulatory limits as to the length of extension that should be used, however with air rifles the overall length of the tube, barrel & action system cannot exceed 85cm - in practise an increase of approximately 5cm is all that can be achieved.