Made from tough long lasting UV stabilized Black HDPE.Note this material will out last any other materials commonly used for this product. 
Suitable for moderately strained fences. 
Length = 71mm. 
Width = 37mm 
slots 10mm x 15mm 
We have been Manufacturing a small Range of insulators for over 20 years. 
you can expect our products to last in the sun for many years.In fact ,we have not seen one of our original insulators damaged by UV as yet.