You probably noticed. Flush mount pop-up gas caps are getting out-dated because seen on so many radical high tech bikes. With the old school trend in full swing, gas caps & shift knobs are getting a new life with fancy shapes like stars, crowns, spinners, etc (check these ones). Here the the most simple design you can find, but you have to know where to buy it. Just a ball shape but with the advantage of working well on 4 of your bike components: gas tank, oil bag, shift knob and mirrors. Made out of solid aluminum and offered in polish, red or blue. Of course, you can anodize yours the color you want to match the color theme of your custom. Offered by David Anthony Customs.