MTB/ SPD Cleat Wedges® work with SPD-compatible cleats and most other side-by-side two hole cleat systems.  BikeFit specifically uses hex bolts for all SPD-style 2-hold cleat applications to provide the most secure connection.

The box includes eight (8) 2-hole SPD Cleat Wedges, two (2) 12 mm & two (2) 14 mm hex screws, an Allen key wrench, and installation instructions (also downloadable below).
  

The 2-hole system is commonly known as the SPD system (SPD = Shimano ® Pedaling Dynamics). The 2-hole system can be used for all types of riding, including road cycling, mountain biking, touring and commuting. When paired with some shoes, the recessed cleat design allows easier walking. Most off-road racing, where a mud-shedding cleat design offers an advantage, is where a small two-hole cleat is popular.