The Aerial Extension Lead is for use with the DualCom GradeShift range G2, G3, G4, FIRE or Emizon TCD. In the unlikely event that the signal received by the DualCom or Emizon TCD is insufficient the Aerial Extension Lead allows relocation of the aerial of up to 5 metres. The maximum number of Aerial Extension Leads that can be used per installation is one, increasing the distance beyond this will cause a significant drop in signal strength.