STX Lacrosse Stallion U 500 Unstrung Lacrosse Head The STX Stallion U 500 is specifically designed for the midfielder The bottom rail of the STX Stallion U 500 features a bottom rail designed for a high pocket placement for additional power when shooting The STX Stallion U 500 meets both NCAA and NFHS requirements for play Features the STX C-Channel technology on the bottom rail which provides extra strength for checking and picking up ground balls