U S type Shackle Forged, quenched, and tempered Meets the performance requirements of federal specification RR-C-271 U S type Shackle Forged, quenched, and tempered Meets the performance requirements of federal specification RR-C-271D Hot dip galvanized or self-coloredSize: 5/8 to 2 1/2-inch, WLL 3.25T to 55TMBS=4 X WLL or MBS=6 X WLL alloy steel S6 shackle RR-C-271