A turnbuckle, rigging screw and bottlescrew are devices used in the tensioning of wire ropes, cables, tie rods and other tensioning systems.

The main difference is the body of the fitting.

What is a turnbuckle?

Turnbuckles have an open body, exposing the threaded section.  Often used in shade sails and marine applications.

What is a Bottlescrew?

Bottlescrews have an enclosed body, hiding the threaded section.   Often used in wire balustrade systems but also in shade sails and marine applications as well.

In additional to the screw bodies there are a few other points of difference.

Turnbuckles

These fittings have the same applications as bottle screws, but have a generally smaller size range and shorter adjustment. The main benefit of a turnbuckle is that it may have a greater ability to be tightened under load. Also, there are a wider range to end fittings.

Jaw/Jaw	Hook/Hook
Eye/Eye	Hook/Eye

Bottlescrews  (Rigging Screws)

Bottlescrews are used to make adjustments and for tensioning and are usually used in wire balustrade systems as they offer a sleeker design.

Another significant difference in this range is that the Bottlescrew can be swaged (crimped) to wire rope, see Jaw/Swage Bottlescrew below.

Jaw/Swage	Jaw/Jaw