The Simon Switchblade with Simon's metal quick change clevis makes swapping spinner blades simpler than ever. We use only stainless steel wire, fluorescent/UV tubing and beads combined with our chemically sharpened 3x strong Seaker treble hook. The Simon Switchblade is designed to work perfectly with 3.5 Colorado spinner blades. You can also use size 3 or size 4 Colorado's with similar results.