(What is it? Do I need it?)
Anti Hot Spot Tape - Is a purposely designed foam tape that is adhered to your framework, prior to polythene fitment, in areas where the polythene will come into direct contact with frame materials. It provides a protective barrier between the frame and the polythene sheet. This prevents damage due to agressive contact or heat damage. It is a proven means of prolonging the life of your polythene.
The tape comes in 19mm, 30mm amd 50mm widths. Citadel will supply (with a polytunnel kit) the number of tapes required for the structure in the correct width.
If you are using horticultural polythene for any greenhouse application, whatever the frame material (steel, aluminium, plastic or timber) you should seriously consider the use of a non-PVC anti hot spot tape. Citadel's hot spot tapes are specifically designed for purpose.