With torque spanner for basic roof carrier, you can always be sure that you have tightened the bolts with optimal torque. Your wrist is strong enough to properly tighten the bolts, but to prevent over-tightening, which could cause the material damage or impossibility of loosening it again. It´s maximum torque is set on 4 Nm. Correct designation the torque spanner you can found on your roof rack.