Rovex Fluorocarbon PVDF Fishing Leader Line is as close to invisible as is possible, sinks four times faster than regular monofilament nylon (mono) and has excellent abrasion resistance. This fluorocarbon fishing leader line is made from premium-grade 100% PVDF, or polyvinylidene fluoride. PVDF is a material with properties that mean optical density is lower than mono making the leader less visible to fish, with a harder surface, which increases its abrasion resistance, that doesn't take up water and it's also resistant to UV light. PVDF is denser than mono, so it will sink faster and will not float. All this jargon simply means that when you need the most invisible leader possible, with better abrasion resistance, and you don't mind it being a tiny bit stiffer, then Rovex Fluorocarbon Leader is your best choice. 20m spools are available from the trout-, bream-, whiting- and bass-friendly 4lb (0.17mm diameter), up to 80lb for the big ones. 100% PVDF FLUOROCARBON PREMIUM LEADER!