Pro-Ratchet 50 With Cheek Adaptor. The Pro-Ratchet 50 features a hardwearing nylon sheave with eight V grips to give an extreme hold on any rope. In the middle of the block is a switch that can be used even under load to turn the ratchet on or off. This version comes with a cheek side plate, to allow mounting to any flat surface. Three screws are required to complete installation.