Adults can be replaced with kids but kids can not be replaced with adults. In this column the materials that the kayak is constructed of are indicated. It is usually lighter than plastic in the same size kayak. Kevlar is like fiberglass but lighter and stronger. This column will indicate if the kayak on this row can have a rudder of not.
Some kayaks always come with a rudder.
Some kayaks can never have a rudder. Many Kayaks have the rudder as an option that can be installed later. This column will indicate the maximum amount of hatches that the kayak can have. On most kayaks, hatches are an option that can be installed at any time. This column indicates the suggested retail price of the kayak on that row.