Trimax Machine Hardened Steel Coupler Locking Pins outperform industry standards in several key ways, from their reinforced construction for sturdy reliability to their triple-chrome finish for an extra-protective layer and sleek finish. Trimax Machine Hardened Steel Coupler Locking Pins also stand above the competition with their O-ring seal and watertight cap for superior corrosion resistance. These Trimax locks will outlast imitator models, and probably outlast whatever theyre hauling. SIZE: 7/8 span. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Coupler Lock.