I purchased the twin lock n level after watching video and reading feedback, the delivery was very prompt, and over the Bank Holiday we had our first chance to try it out on a caravan rally. The instructions are very easy to follow and within a few minutes we had our caravan leveled up.It did the job perfectly for the whole weekend. On removing it the caravan weight took most of the air out, it just took me a little while to get the last of the air out so i could get it back into its bag.I am very impressed by the lock n level and would have no hesitation in recommending it, thanks for an excellent product which does what it says on the box.