This is a top mount filliment sensor holder for the Ender-3 V3 plus. This will allow you to put the filliment above and behind the printer and prevent the filliment from getting tangled around the built in holder, as it sometimes does. Print it on it's side for the strongest result with the least waste. You will need 2 3Mx10 bolts, 2 3Mx20 bolts, and 2 3M nuts to assemble, as well as a short JST XH 2.54 connector cable.
To install first position it at a 45 degree angle off to the side of the center with the opening facing the top rail, then put the top lip of the mount onto the top of the printer, and pivot the mount into position, once there you can slide it to the middle and attach the 2 3Mx10 bolts. After you have removed bowden tube from the filliment detector, remove it from its original position by removing its bolts and the JST connector. Then slide the original cable out of its sheeth until you get close to the right support strut. You will probably need to cut a sticker to do this. Then mount the dector using the 2 3Mx20 bolts and the nuts. You will need to place the nuts into the mount and hold them with a finger as you tighten. Be careful to not over tighten, this is a plastic mount. Then you can zip tie the original wire to the support strut and the top of the printer and attach the extension to it and the detecftor. You will probably want to trim the tube as it will be to long if you dont. I just homed the head and left a few MM of slack and cut it.