24" hd i-beam level. Heavy-duty aluminum frame assures durability and accuracy. Top read window maximizes readability. Durable easy-read acrylic vials are impact-resistant. Quik-Change replaceable cover plates and vials for in the field service. Shock absorbing end caps protect frame. Length: 24", Material: Aluminum, Type: Tubular Spirit, Style: I-Beam, Total Number Of Vials: 3 No. 3748: Length: 48", Material: Aluminum, Type: Tubular Spirit, Style: I-Beam, Total Number Of Vials: 3