Each pay-off structure is made of bent and welded steel tubes and sheets and provides a mounting for two spools; one is in working position and the other is in standby position. Each position is designed for paying-off the wire alternatively from one of two spools; when paying-off the wire from one spool, the other can be substituted and wire welding can be easily made.

The spools are loaded/unloaded with vertical axis from the top side, by means of a crane.