The 16mm is Harken's 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) safe working load - the highest on the market compared to similarly sized blocks.
The 442 uses a spacer and the 404 uses an o-ring to keep the line in the sheave during intermittent loading.
Use for: dinghy control lines, big boat leech lines, down hauls, traveler controls, spinnaker pole trip lines, out hauls, cunninghams, halyards on prams etc