HIPLOK uses a four tier security rating system featuring Basic, Medium, High and Maximum levels Secure reusable zip like tie with extended locking circumference and featuring a combination lock mechanism for use on car racks, with accessories and other outdoor equipment Secure reusable zip like tie with extended locking circumference and featuring a combination lock mechanism for use on car racks, with accessories and other outdoor equipment Z LOK Combo offers the same ground breaking lightweight, adjustable zip like tie design as the original Z LOK but with the added benefits of a larger locking circumference and reset-able 3 digit combination mechanism Steel core, toughened nylon outer design, provides versatile protection and security for all manner of applications 40cm/15.75` locking diameter