Unbreakable cat flap

[cocopops]

I have had my eighth plastic cat flap wrecked by my dogs sticking their heads through it.  I have left it broken all summer but now I need to replace it again.

I have noticed that there are alluminium cat flaps available but I wonder how strong these are.  Has anyone used one?  I would have raised the flap higher, or maybe through a window, but one of my cats is quite elderly and none to agaile these day.

Any suggestions would be appreciated.

[cocopops]

[star]

Sorry Coco, I havent seen one in alluminium. I would imagine they are stronger........but I am guessing :-\