The Swivel-Lock Carpet Stretcher head gives you the benefits of both straight and swivel carpet stretcher heads in one. The head has a 60-degree range of free swivel for stretching patterned carpet. By depressing the built in lock pin, you can lock the swivel in 5 convenient positions. There is even a 30-degree setting for extreme angles found in “l” shaped living/dining rooms. This is the power unit only, tubes and case not included. This is the power unit that comes in the Crain No. 520 Double Case Carpet Stretcher.