Just thought I'd pass along this idea to those who like to build stuff. I had a couple of those el-cheapo little 3-digit Chinese voltmeters and some very small project boxes. I wanted to make little voltage displays that one could attach to a power supply, battery pack etc. I used an Xacto type blade to cut the openings in the boxes, but as carefully as I tried, I had an uneven opening that showed gaps between the project box and the meter. I found a product called Sugru Mouldable Glue. It comes in packets and is sort of like a putty. I cut off thin strips, pressed it in place around the meters, and smoothed it out with a wet finger. I think it turned out OK!