I used them to access the batteries on my 200q Roadtrek RV. Checking the electrolyte in a cell is very difficult due to the layout of the batteries. Difficult to remove batteries for inspection but almost easier than in place. So I bought a quick fill to solve this problem. The distributors fit well and are easy to assemble. Cell covers are well designed to reduce outgassing when containing electrolyte. Everything seems to be of good quality. I think the system costs more than it should, especially the pump. But I have found the support team to be quick to answer my questions. Is the effort justified? The time will show.