Offset base design allows for larger usable work area beneath I-beam. Allows for easy transportation of jib crane with fork truck. Fixed length I-beam will pivot 360° for complete access. Base with jib crane is filled with concrete. Offset base size is 42-3/16" W x 42-3/16" L x 18" H or 36" H. Built-in fork tubes measuring 7" W x 2" H usable for transportation with fork truck. Steel construction with blue painted finish. Units ship knockdown. Not for use as a fork truck attachment. 10' under I-beam.