ND Industries’ reactive thread locking processes apply dry-to-the-touch chemical adhesives to your internally or externally threaded fasteners. During fastener installation, the microencapsulated components mix together, causing a chemical reaction which locks and seals the mating parts. With ND’s Expand-A-Lock formula a 20-50% material expansion also occurs, filling the gaps between mating fastener threads and creating the highest strength threadlocker available.