Circlips

Circlips (also known as Retaining rings or Snap rings)are semi-flexible fasteners designed to fix elements onto a shaft or in a bore/dwelling when assembled in a groove. seals or scraper rings on the cylinder rod.

Circlips, Metal O & C Rings, PTFE Seals & Spring Energized

What is a circlip? - Wonkee Donkee Tools

External Circlips, DIN 471, JIS B 2804 Standards

KNIPEX 46 10 100 - 9138 Circlip Tool for internal and external circlips up to 1000 mm nominal size

There are two types of retaining rings, or circlips, internal and external. The best way to identify which is which is to look at the tabs where the tool pins go. If they're on the inside of the circlip, then it's an internal circlip or snap ring. If they're on the outside, they're external. Pretty simple, right? The two types require different tools. Internal circlips are squeezed to free them (or install them) from their slot while external retaining rings are spread open.