Quality Assurance ----- The Ruler Body Is Made Of Solid 6061 Aluminum Alloy And The Rotary Knob Is Made Of High Quality 100% Pure Brass. Comfortable Feel. All Scales Of The Ruler Are Laser Engraved, Accurate, Clear And Easy To Read. Tracing Function-----Use The Small Hole As A Starting Point, Adjust The Length You Need, Hold The Ruler In Your Left Hand And Draw The Lines With Your Right Hand As Needed.Measurement Function-----Move The Limit Block To The Top Of The Ruler, Tighten The Knob. The Ruler Turns Into A T-Ruler For Daily Measurement.Perfect Design-----Bilateral Scale, You Can Use The Scales On Both Sides Of The Ruler As You Need. Precise Operation: 1 Mm. Flexible And Easy To Use. Let The Scribe Do What You Want, Meet All Carpenter'S Square Wood Scribe Needs. A Great Gift For Friends Who Love Woodworking. Lifetime Warranty ----- We Strive To Provide The Best Products. Homewins Customer Service 12/24H Online To Answer You, If You Have Any Questions, Please Feel Free To Contact Us. 100% Refund Or Replace If You Are Not Satisfied.