The 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.

Sheave (mm)16mmLength (mm)29mmWeight (g)10gMaximum line (mm)5mmMaximum working load (kg)113kgBreaking load (kg)544kg