Friction-ring stem casters each have a stem that presses into an appropriately sized hole or socket in tubes, pipes, wood, or compatible brackets on furniture or equipment. A spring ring at the end of the stem expands to hold the caster in place once it's installed in the hole or socket. Also known as grip-ring stem casters, these casters are used on furniture or equipment such as office chairs, tables, and medical equipment to allow them to roll as they're being moved or repositioned. Friction-ring stem casters require few or no tools for installation, making them well suited for applications where casters need to be replaced frequently. These swivel casters can rotate 360°, allowing equipment to change directions while rolling.