This Loos economy tension gauge takes the guesswork out of cable tension adjustment. It's especially designed for accurate, repeatable tuning of a sailboat's standing rigging. Manufactured of rugged anodized aluminum, the gauge is corrosion -resistant and will provide years of service. The LS91 and LS91M is sized for smaller cables measuring 3/32 to 5/32 inch thickness. The LS90 and LS90M is a bit larger and sized for measuring cables from 3/16 to 9/32 inch of thickness.