I just used this item flat,
Refrigerator bar, enough room to put wash cloths and hand towels, put two side by side and made a nice temp shelf in the upper bath cabinet which really is rather tall and ours measures 13" wide. I'll take pictures next time I'm there but I'd rather find something that's' more permanent although this was amazingly secure. I hate to put holes into things :)
For steadying we use the Lynx wheel chocks to start, then add these: the BAL X-Tended X-Chock both sides, 4 Camco Stack Jacks and the original scissor jacks. You'd think that would be enough but it's not and NO I'm not asking for the world here! Just watch the coffee in the coffee pot slosh back and forth. I should take a video of that! Hey, not really complaining this is the best camping I've ever done!