€¢ V' groove on bottom of frame for use on round pipe; conduit; or flat surface €¢ Lightweight extruded aluminum I-beam frame €¢ Made in the USA >> Lightweight extruded aluminum forms this 48 inch I-Beam frame. This level is engineered to meet the demands of the home handyperson. Three bright yellow vials are set for accuracy. The solid set; replaceable Roto Vial® protective plastic lenses an vials. A groove in the bottom of the frame is ideal for rounded surfaces such as pipes and conduit. Large hand holes provide comfort and ease when moving the level. A hang hole on one end allows for easy storage when not in use. Store in a Professional Level Case (#SLPLC48); sold separately; to protect your level and extend its life. Proudly made in the USA."