what is a shock leader? and do you need one

answer:
if you are using 15lb main line and cast a 5oz lead the chance is your line will brake/snap.
so to combat this we use a shock leader which is a length of line stronger then your main line.
as a rule of thumb for 1oz of lead you need 10lb of line so if using up to 6oz leads you need a 60lb line for your shock leader.
as for the Length of your shock leader, set your rod and reel up take your main line up and tough the top eye and Tye your 60lb shock leader on.
wind the reel till the shock leader reaches it then do 4 more full turns of the reel then leave about a foot of shock leader at the end of the rod and cut, i Tye on a swivel to attach my rigs (make sure the swivel will go though your top eye)
hope this helps.