I used this for a while. Though hollow plastic I felt it was designed to hold a camper from rolling and it did. One day I forgot to remove it when pulling out and it seems to take very little pressure moving forward to flatten it like a pan cake so I though my 50,000 investment may be better served with a heavy duty galvanized wheel chock that won't give in and even let me move over it by mistake and let me know its holding solid if I ever did again roll forward over it.