Estes 302227 Tube Marking Guide
The Rocket Builder’s Marking Guide with Fin Attachment Guide makes tube marking easy and simple. It allows you to mark reference lines down and/or around popular Estes model rocket body tubes. The ruler is scaled for either metric or "  measurements. A pencil holder to mark tube circumferences and a fin gluing jig are molded to the ruler for accurate marking and alignment. Special disks are also included for marking 3 and 4 fin spacing with precision. The Rocket Builder’s Marking Guide is the perfect tool for any serious rocket builder saving time and money when building any model rocket.