Spinlock's Lightweight Shackle Fid is a snap shackle tripping spike with a hand grip designed to give you better control at high loads. You don't have to have a Mast Pro Harness to use it, but it was designed to fit perfectly in its special pouch. Engineered in alloy with a bored out center, it is almost half the weight of traditional spikes, and it has been dimensioned to work with snap shackles up to a Tylaska T-20C. It also has a lanyard attachment point.
And, of course we can sell you the Mast Pro Harness - Mark II (SPDWPSG).