works perfectly came on time small tubebut you dont use much for a thermostat im not sure why some reviewers think this is too small but i liked them appear to be holding up just fine best wheel chocks for large trailers boats good for the big wheels on the rv great product for the money light weight easy to move in place like the size since i have a 36 ft fifthwheel they chock wheels good stops my 74 vette from rolling down the does what it is supposed to five stars inexpensive and easy to store in my dual axle right size for the 5th wheel