Continuous Dual Rail Frame Allows For Continuous Scribes Without Frame Interruption While Adding Protection To The 0degrees Vial • Exclusive Diamond Bumpers Are Raised Slightly To Grip Material Surface And Eliminate Marring • Gelshock End Caps Are Silicone Gel Which Absorb Shock To Withstand Severe Drops • Acrylic Block Vials Have Multi-Rings To Quickly And Easily Determine Pitch Of Grade Or Slope With .029degrees Vial Accuracy