Connection for your LED tank probe to the first stage. The 15 cm HP tube allows you to distance the LED probe from the first stage for better reception in more complex configurations.Allows you to move the LED probe module away from the first stage. Ideal for improving signal reception in complex configurations. The 15 cm HP tube allows you to move the LED probe away from the first stage. Helps prevent breakage due to the module crashing or the tank tipping over.