General description Polished finish quality open body turnbuckles, commonly known as rigging screws, straining screws, and barrel strainers. Technical specifications D1 (mm) - M20 L (mm) - 300 L1 (mm) - 440 D (mm) - 30 Material - A4 grade stainless steel (type 316 S31) Corrosion resistance - Greater than A2 in certain environments Other information Ideal for marine applications, especially in direct contact with salt water.