One piece construction to provide consistent performance and reliability. Self Locking Nylon Cable Ties. Extra strength due to heavier weight of material used. High quality High quality Nylon UL approved, resistant to most chemical acids. Additives for UV protection - Black Cable ties, suitable for continuous or extended exposure to outdoor sunlight. Resistant to most chemical acids. RoHS compliant. Packaged in handy zip lock resealable bags. Extra strength due to heavier weight of material used. Packs of 25, 100 & 500