The F.P. 4 Freezer spacers is unidirectional and is designed for single airflow through freezer tunnels. The spacer height of 55mm has far greater unrestricted airflow for maximum freezing efficiency. The spacer eliminates carton damage in cold and damp environments. The smooth corrugations prevent carton penetration and tearing. The unit size is 1180 x 1180 and is made of food grade polyethylene. It has a life expectancy in excess of 5 years and is guaranteed against cracking for 2 years.