An eye bolt is a bolt with a loop at one end. They are used to firmly attach a securing eye to a structure, so that ropes or cables may then be tied to it.
Heavy forged eye bolt, with shoulder
Machinery eye bolts are fully threaded and may have a collar, making them suitable for use with angular loads up to 45°. Eye bolts without a shoulder should not be used for angular loads.
Heavy forged eye bolts with a continuous eye may be forged with an integral shoulder, allowing their use for heavy off-axis loads.
Eye bolt with integral wall anchor
Eye bolts are often installed into masonry and so versions that form their own anchor bolt are commonly available. Most of these screw into some form of shield anchor. Some lightweight forms are not screwed, but rely on just the pull on the ring itself to expand the anchor.
A ring bolt is an eye bolt with a captive ring passing through it. The loose ring is articulated, such that it can rotate in at least one axis, and can thus reduce bending forces on the bolt when loaded and will present the minimum obstruction when "flat".