The Snap-on 3/8"-drive Ratcheting Extension/Speeders come in two sizes: 3" (FXKR3) and 6" (FXKR6). The applications for the FXKR3 and FXKR6 include engine compartments, spark plug installation, under dash applications, electrical harness mounts, air conditioning/blower modules and headlight/brake light assemblies. In addition, they can also be used for small engine repair, motorcycles and boat engine repair. These extension/speeders offer users control and one-hand operation with a built-in forward/reverse lever activated with a simple thumb movement so users can sense how much force is needed to snug fasteners.