Without any doubt, when fishing on a hard gravel bottom inline leads hook the carp quicker than swivel type leads. The reason for this is that the fish always pick up the lead from the heavy end first, because the hook link is always attached to the heavy end of the lead. In the case of Korda inlines the swivel is actually semi-fixed inside the lead, exaggerating the 'instant bolt' effect. What Dan set about doing after watching the fish hooking themselves on Part 4, was to design the most condensed shape of lead possible. So, a fish would have to move the minimum distance before it felt the full weight of the lead. Now, the most condensed shape of all is a ball, but a ball could possibly roll around before the full weight is felt and it isn't tapered towards the back of the lead enough to stop the hook link tangling around it. So, Dan chose to put four flat sides onto the ball and gently taper the back to avoid tangles. An appropriate name that summed up the lead, was of course the Square Pear. As an inline there is no lead out there that the fish will feel the full weight of more instantly. Even as a swivel lead, the fish will still feel more of the weight sooner because it's so short and one end of the lead is almost the same as the other. Only the movement of the swivel will make a difference. So in short, you have the most condensed inline lead and swivel lead there can be, with flat sides that works in a fishing situation.