The rigging foam is durable, sturdy and reusable. Includes four (4) each in an off-white color. The larger size allows you to rig multiple nymphs, tandem rigs and dropper rigs for any size flies, or just a singe dry fly or nymph on a leader and/or tippet. The rigging foam allows you to pre-rig flies and quickly change them on the water. The spools are 2 3/4 inches in diameter, 3/8 inches thick with a 5/8 inch hole for mounting on a tippet type holder.