The Jurassic Insulator is used with square tube brackets, and square or round fencing posts. Available in feed-through or slott Features: Large electrical tracking distance to reduce arcing in areas where there is pollution and salt build up Feed-through option for maximum security Slotted clip option available for a quicker wire placement Self Tapper Hooks are used to fasten the Jurassic insulator to the bracket or post and is available in two sizes Easy to change and maintain