These are machined for our Camburg X-joint upper control arms. These cap off the top of the arms to protect the Camburg X-joint or Moog ball-joint and utilize an O-ring seal and press fit. We machine these in-house from 6061-T6 billet aluminum, anodize them black and laser our trademark Camburg logo on them. For 05-22 Tacoma owners you will need to measure the diameter of your existing cap or the machined cup the ball-joint presses into to order the correct version since we offer two sizes.