Here is a pro tip: Don't ruin a $1,500 leather suit by wearing a cotton t-shirt underneath. The D-Core Aero is the unsung hero of track days. It makes sliding into tighter-than-skin leathers effortless and actually keeps your core temp regulated, wicking sweat faster than you can generate it. The compression structure reduces muscle fatigue by stabilizing the muscle groups, which sounds like marketing fluff until you're on lap 20 and your arms aren't jelly. It fits tight—like a superhero costume—but that's the point. Once you ride with a proper technical base layer, you realize that comfort isn't just about soft materials; it's about climate control. Essential kit for any serious rider who wants to stay cool and focused.