I just wanted to share photos of my rheostat receptacle. I have three of these to control my under tank heaters. If anyone wants it, I could write a article on how to build one with photos. It can be used to adjust/dim lights, heat pads, and heat tape. This is the one I built today. I write on the box where off and hot is. I also put a line on the knob and I put two lines on the box its self, one for my summer setting and one for my winter setting. Seems to work pretty well.