FOPS – closure rings protecting from infiltration of humidity

Original patches for protection from infiltration of water/moisture into the joint, through the foaming openings. They last over 300 cycles in sand-box test at sand humidity below than 0.5% and over 1000 cycles with sand humidity below 8%. Surface of FOPS patches are with permanent dotted green indicator (disappearing in case of appropriate heating) securing correct assembly and tight sealing.