HK needle sleeves according to DIN 618-1/ISO 3 245 are needle bearings with the smallest radial height. They consist of chipless formed, thin-walled outer sleeves and needle crowns, which together form a structural unit. These bearings enable particularly space-saving and assembly-friendly installations with high radial load capacity. Needle sleeves are open on both sides and are supplied with needle crowns or fully needle-based. Bearings with needle crowns allow for higher speeds compared to fully needle-based versions. Fully needle-based needle sleeves have the highest load capacity in the smallest installation space due to the maximum number of needle rollers. However, their use at high speeds is limited.