To customize running shorts with built-in liners: (1) choose outer shell fabric — lightweight polyester for speed or nylon for durability, (2) select liner type — compression brief style (minimum inseam 3-4 inches) or boxer style (5-6 inches), (3) use moisture-wicking mesh for the liner to maximize breathability, (4) add side slits for range of motion. AOLAFREE offers split shorts, 2-in-1 shorts, and traditional shorts with liners. Sample: 2–3 weeks.