Harken Stand-up bases allow a wide variety of blocks to be
held upright, swivel freely, or pivot so lines have a fair
lead under load.
Use the1634 Harken stand-up base with Harken Midrange blocks
and 57 mm or 75 mm Harken Cruising ESP blocks. Block
headpost fits into socket without shackle. The
low-profile design is ideal for mastbase and
halyard lead blocks.