Akron Brass Akromatic [737] 1250 GPM Foam Tube. Akromatic 1250 Foam Tube. The Style 737 Foam Tube is designed to simply and quickly clip on the Style 5177 Akromatic 1250 nozzle. This new foam tube will provide the capability to air-aspirate foam up to 6:1 expansion ratio with AFFF foam.