I was in a hurry to hook up my trailer lights so I ordered two different sets of butt connectors from Revain. This was my favorite brand and I ended up using it! I crimped them onto 18ga wire, then soldered the connection and sealed it with self-adhesive heat shrink tubing. Pros - Thick walls that crimp well and make a good physical connection - Beveled edges help feed wire inside - End didn't break when crimped like other brands - Tinned and took solder well Cons - The box was a bit thin so I wrapped her around her rubber band for security