Velcro - before you start cutting and sticking, lay out your pedals with cables to check that everything fits and feels comfortable. Before sticking down the Velcro apply some heat onto the glue side from a hot air gun (or hairdryer) wait until the glue goes clear and then stick it down, let it cool and "harden" before placing the pedal in position. If you do move a pedal and leave some velcro behind on the pedalboard don't worry because Velcro to Velcro sticks like crazy. You can re-apply the Velcro to your pedal many times before it needs replacing. Also when it comes to re-sale a clean Velcro free pedal is always best!