This item no longer for sale. Thank you for your interest.
AVL Tension Box, gently and occasionally used. Helps maintain an even tension when winding on to a sectional beam from a cone/spool rack. You can read about it here: https://www.avlusa.com/catalog/warping-accessories/tension-box/tension-box-standard/
The Tension Box sells for $375.85 new. Pick up in Charlottesville, VA, for $75.