16mm BlockThe 16 mm is Harkens smallest block. It is perfect for small synthetic control lines found on high-tech dinghies. The patented bearing system uses stainless steel balls in a captive grooved race and has a 250 lb (113 kg) maximum working load. The 404 uses an O-ring to keep the line in the sheave during intermittent loading.Specifications:Sheave: 16mm / 5/8in.Length: 29mm / 1-1/8in.Weight: 10g / .33ozMaximum line: 5mm / 7/32inMaximum working load: 113kg/ 250lbBreaking load: 544kg / 1200lb Manufacturer : Harken Manufacturer Part No : 404 UPC : 097653014904