Standard 220SW Hailer Horn 20 Watt 4 Ohm20 Watt 4Ohm speaker horn. Use this with any standard radio that has a built in hailer 20watts or less in power. If the hailer has listen feature this 4 Omh speaker will perform the listen feature.Features of Standard 220SW Hailer Horn 20 Watt 4 Ohm Power - Output (Watts) 30W|Shape NONESpecification of Stan..