Its the Type H-1 suitable for all Nissans, HKS part number 4605-RN001
Spec from the HKS site:
The HKS EIDS has been developed to buffer dramatic airflow meter signal fluctuations. By buffering these fluctuations the EIDS prevents engine stalling or stumbling associated with sudden imbalances in air/fuel ratio of airflow meter-equipped vehicles that utilize atmosphere venting blow-off valves.
Comes complete with instructions
£80 including next day delivery