Small Boat Furling Swivel.A top swivel furling unit is a component of a headsail furling system. It's positioned at the top of the forestay and works in conjunction with a drum furler or continuous line furler at the bottom of the forestay.The swivel unit consists of 5 rows of ball bearings for reliable and smooth rotation of the drum when under load.The swivel body is manufactured from marine-grade aluminium.This top swivel is typically paired with the A4305 Ð Drum Furler or A4907 Ð SwiftFurl Continuous Line Furler.