What are the differences between the SH56 and SH51 cleats for cycling shoes?

The main difference between SH56 and SH51 cleats for cycling shoes is the release mechanism. SH56 cleats allow for multi-directional release, making it easier to disengage from the pedals in various directions. On the other hand, SH51 cleats only allow for a single-direction release, which may require more precision when disengaging from the pedals.