A long-time neighbor of mine where I grew up in upstate NY makes these snap-over wire markers as part of his plastics business. They are a 3/4 circle of plastic that pops on your plug wires. If you have ever swapped a plug wire while fixing some other issue and then spent 20 or 40 or 400 minutes chasing your tail, you can appreciate why this is a good $5 investment. Over the holidays I stopped over and got a few sets. Thought I would put in the good word for a small business -- not made in china -- made in 12123! You can buy them at jegs -- use the small ones for stock wires or get the bigger ones for 8/9mm wires.