 The outer tooling strip often includes tooling holes, a set of panel fiducials, a test coupon, and may include hatched copper pour or similar patterns for even copper distribution over the whole panel in order to avoid bending.The assemblers often mount components on panels rather than single PCBs because this is efficient.Panelization may also be necessary for boards with components placed near an edge of the board because otherwise the board could not be mounted during assembly.