Click to expand Tap to zoom PetSafe Staywell Tunnel Extension 310 fits 300, 400 & 500 Cat Flap White Sold out £8.48 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Sold out Tunnel Extension - White 2" (51mm) Tunnel Extension suitable to extend to any depth Fits all 300, 400 and 500 series Staywell cat flaps.