These rubber flaps from Spal are designed to be used in conjunction with custom fan shrouds to improve the cooling performance. The flaps work by allowing air to pass straight through the shroud when the fan is not operating increasing the cooling efficiency. When the fan is switched on the flaps are sucked closed preventing air from bypassing the radiator.Ideal for use with custom fan shroudsImproves cooling efficiency when the fan is not operationalNitrile rubber construction suitable for temperatures up to 110° CDimensions: 83 x 48mmSold individually