My trolley itself is great, I am concerned that now in my second season replacement parts are looking to be impossible to find on website. Replacement batteries, 5th wheel replacements, keypads for remotes and the parts and pieces that I think I am going to need very soon are simply out of stock every time I look. That is quite a bit of a concern as I approach the 300 mile mark on my Zip Nav A/T. My remote buttons are starting to be less responsive from wear is my guess and I do not see the ability to find that part for a long time - and a total remote replacement cost is almost 15% of an entirely new unit.......starting to be concerned. If the cost of the smaller and easier replacement parts are always out of stock and/or inherintly expensive - it makes the unit utility far less appealing and cost prohibitive.