I am very happy with the product, it makes it so easy to level up my twin-axle caravan and enable me to fit my second wheel-lock. Perhaps I am worrying unnecessarily , but, am more than happy to take any advice with the following. I use the kit when parking-my caravan for storage to put on the second wheel-lock, this means leaving the air-bag under the wheel whilst stored. Following a period of rain/snow I find the wheels are sitting in puddles of water as the water is unable to drain away from the surface of the bag when deflated due the outside edges sitting higher than the centre areas . Do you have any ideas, just a personal concern as otherwise a ‘great bit of kit.