Hi Tae, Actually I have a few small skulls that I use as molds. The thing with this one is that it had to get more narrow to fit the iPhone case. This gives it the look it has now. Kinda Sleestack look I guess (SP?). Wet your leather and start to form it over the mold while blowdrying it. Take your time and it will shape. Then just form it to place and stitch it and trim. The skull is hollow but will hold it's shape after it dries.