Swivels that let a hose reel turn while the water keeps flowing. The swivel is the part that wears, and on a reel in daily use it is the part you will replace first. Choose by port size and by pressure rating - a swivel rated to 3,000 psi on a 4,000 psi machine will weep, then fail.

Match the port thread at both ends, not just one. Brass bodies suit general wash duty, stainless suits hot water, chemicals and coastal work. If your reel is a known brand, order the swivel listed for it rather than a generic one, because the mounting spigot length varies and a close fit is what keeps the seal square. Seal kits for most of these are listed separately, so a weeping swivel does not always mean a new swivel.