The Jurassic insulator is used for square tubing brackets.

The Jurassic insulators have the following features:
• a much longer tracking distance for less arcing in areas where there is pollution and salt buildup
• feed through option to thread the wire for maximum security
• slotted clip option available for a quicker wire placement 

They are available in black.
 

• Diameter of mounting hole-6.2 mm
• UV stabilised for external use