If I'm not mistaken you are showing the hairpins that lock the lynch pins on your 3-point stabilizer arms. I use hairpins at that location and have narry lost one. Now - go down lower, where your 3-point arms attach to the rear differential housing or whatever. I've lost a few at this location. I now use high carbon bolts and Nylock nuts.
After all the searching and finally using these bolts & nuts. The neighbor takes a pair of pliers and makes a 45 degree bend in the final inch of the straight leg of the hairpin. Like me - his only reason for removing the 3-point arms would be to repair damage.
Roy, i've been looking for these as well. I dropped one and it's long gone. i was using cotter pins for a while, then a piece of rebar wire. then i gave up and don't bother using anything. Ive bladed a few miles of road, mowed a bit with the brush mower and have yet to loose a pin. I'm likely just lucky. At least i have some luck somewhere....
I find i was pulling those pins almost every implement change. Gotta have something quick and easy.