I’ve always liked the X Rating approach to tippet rather than breaking strain, though it’s more common in the US than the UK. Modern tippet materials are exceptionally strong, largely due various treatments and coatings they’re given to improve breaking strain and resistance to abrasion. However, when it comes to working out what a tippet is made of, manufacturers and distributors don’t make things too easy. In essence, there are three basic kinds of monofilament used for fly fishing tippet: nylon such as Stroft GTM (many of which these days are copolymers, a term that simply refers to a mix of nylon polymers being used), fluorocarbons such as Airflo Sightfree G3 (confusingly these can also be copolymers – a mix of fluorocarbon polymers) and hybrids such as Rio Powerflex or Asso Double Strength (copolymer nylon coated with a fluorocarbon, PTFE in the case of Rio Powerflex). At times, working out which is which is almost impossible from the labelling alone.