One thing that I like when I work on equipment or have to turn knobs is one that I can grip and turn easily. What I have found out that a lot of the valve controls that I use, where it be at home or when I was working is that after time original knobs and handles need to be replaced. What I do is try to find a replacement handle that is easy to grip and turn. I like to use four-arm control hand wheels, whenever I get the chance. They are easy to grip and to me, they seem very agronomical resulting in economy of movement when I need to use them.