What is the difference between a traditional guitar pedalboard and an expandable pedalboard?

Traditional pedalboards are fixed in width, leaving you with no room for more pedals. Expandable pedalboards, like XPND, are designed to adjust in size, so your board can grow or shrink as your rig changes. Instead of replacing the entire board when you add or remove pedals, you simply expand or shorten it to fit your new setup.