Line clips are used to cast to the same spot time after time. This allows an angler to hit a feature on each cast, and can be used on the marker rod and the fishing rod.
The usual method would be to identify a feature to cast to such as a silt bed or gravel bar using a marker rod (or just an island or a far margin), and then cast the fishing rod to that point with no bait attached and clip up. At this time the point on the line which would be clipped up is tagged with pole elastic, power gum or some bespoke line that is fluorescent. This will enable the angler to detect the correct distance for the next cast.
Following this the hookbait and any desired addition such as a stringer or PVA bag can be attached prior to casting; the angler then has to cast out with sufficient velocity on the correct trajectory in order to get the baited rig to hit the correct spot with the line clip preventing overcast.
By utilising the same method on the marker rod the angler can accurately bait up the spot using a catapult or throwing stick.
Here are some links to useful articles about line clips on external webpages:
Watch videos about line clips-