If you have put down and removed tape you know 3" is a much cleaner install vs. 4"
You want more mat, less tape.
I put down 4" last time on my own mat and it cracked in the center faster so I went back to 3".
4" is simply too wide, leaves more mess if kept down for extended period of time, and creates more possibility of air pockets. 3" is perfect.
This sale is for 3" width mat tape 6-Pack.
Each roll of tape is 3" in width X 84' in length.