Our J/70 Clew Blocks are all great options depending on preference. The first option uses smooth running ball bearing Harken 40mm Carbo T2 Blocks that provide easy adjustment under load. Their composite construction protects the mast from dings. The second option is built the same way, but utilizes 14mm Harken Lead Rings that offer low friction and less moving parts. Both are designed to be luggage tagged to your jib.