This is the part number for the foam tubing from McMaster-Carr. I checked, the number is still applicable.
2ea 4339T8 Ultra-Weather-Resistant EPDM Foam Tube, 3/4" OD, 1/2" ID, 6 Feet Long
Jul 17, 2020 price each: $10.93
I used compressed air, blown through the "front" of the metal tube...