Needle-roller bearings operate in tight spaces — for example, in automotive applications such as rocker-arm pivots and transmissions. In short, these are roller bearings with rollers having a length at least four times the roller diameter. The large surface area of the needle roller bearing lets them support extremely high radial loads. Usually a cage orients and contains the needle rollers. The outer race is sometimes machined into the housing interior. Needle-roller bearings come in two different arrangements — a radial arrangement (in which the rollers run parallel to the shaft) and a thrust arrangement (in which the rollers are flat in a radial pattern and run.