Dog Collar Hardware

Snap hook on a leash

In addition to basic buckles, dog collar hardware items also include:

D-rings - typically used as an attachment point for dog idenification tags. They may be made from either hard nylon (plastic) or a variety of metals.
Slides - used for collar adjustment.
Snap hooks - these clasps are usually part of a leash, and may attach to the collar via the d-ring.
Solid O-rings - used along with chain in martingale assemblies.
Split O-rings - identification tags are attached to the split o-ring, which then attaches to the d-ring on the collar.