SureFlap Microchip Pet Door Tunnel Extender (White)
The SureFlap pet door tunnel extender fits snugly onto the tunnel of the SureFlap Microchip Pet Door and multiple extenders can be stacked together to form a tunnel of any length. The tunnel of the SureFlap Microchip Pet Door is 2¾" long and each pet door tunnel extender adds 2" to the length of the pet door's tunnel.