A Needle Roller Bearing is a type of roller bearing that uses cylindrical rollers with a small diameter, which are called needles, instead of the larger balls found in other types of bearings. The needles are held in place by a cage or retainer, which keeps them evenly spaced and prevents them from contacting each other.

Attributes:
• Has linear contact areas with outer rings to distribute loads on the larger surface area.
• Designed to reduce friction and improve efficiency.
• Provides high radial stiffness.
• Designed to operate in high-temperature environments.

Applications:
A Needle Roller Bearing supports the high radial load in the Piston.