Line
There's no fishing without line so make sure you've got the right kind for your casting needs. There are 3 main types of line which is Monofilament, Fluorocarbon and Braided and they all have different purposes. Monofilament is generally the cheapest option due to its easy manufacturing process but has great qualities such as holding its shape well and being able to stretch for those hard takes. Fluorocarbon is great for the high end carp angler who doesn't want to spook fish so easily as it vanishes in water and makes it much more difficult for those carp to see when they're closing in on your rig so will increase your chances of a take. Braided line is a mixture of multiple fibres which allows for incredible strength so for those anglers targeting monster carp this option is brilliant for you. Braid is a heavier denser line so would be more advisable for ground hook links than those fishing a distance off the bottom so do bear this in mind with your method of fishing.
