I dont know, that is a mystery of the ages. Today I opened the hood to finalize the routing of the AFR sender, kinda around the brake booster, etc. and opened the cap to the clutch master cylinder just to look. I set the cap to the side just for a second to get a flashlight and rag and when I came back I knocked it off the brake master cap. No biggie, I will grab it when I get done with the routing of the cable. Started looking figuring I would see it on the garage floor, crossmember, etc. Hmmm, no where to be found. I started looking with the flashlight, where did it go? Finally after a few minutes I found it perched on the case, the little wide section of webbing underneath the header. Ok, got this. I reach down there with my meat hook, knocked it off the "ledge" and heard it fall. Musta hit the concrete. Nope. I looked for a considerable length of time, no findy. So I jacked up the front end, crawled underneath a looked and felt everywhere I possibly could. It vanished. I was lucky to find the top off of a can of PVC glue, clipped the swab off it and it fits and seals. Will I ever find it? Maybe, maybe not but for the time being it is partying with the 10mm sockets, somewhere in limbo.....