18”, Black Super Heavy-Duty 250lb Cable Ties, 50 Pack
https://nsiindustries.com/product/18-black-super-heavy-duty-250lb-cable-ties-50-pack/
PowerGRP cable ties are guaranteed rugged and powerful, with professional-grade strength and a self-locking design. The traditional serrated locking mechanism provides a secure grip and the bent tip allows for easy insertion.