Approved bunsen burners Recommend this tubing for Bunsen burners: Tygon S3™ E-3603.
Tygon® S3™ E-3603 Non-DEHP Laboratory Tubing | U.S. Plastic Corp. (usplastic.com)

TYGON PVC Tubing, SAE, 1/2 in Inside Dia., 1 1/8 in Outside Dia. – 22XH84|ACF06040 – Grainger

Humboldt H-2087 Accuflame Gas Line for Bunsen Burners, Flexible Steel Covered with Rubber runs about $48.50 to $54.41.
Humboldt H-2087 Humboldt H-2087 Accuflame Gas Line for Bunsen Burners, Flexible Steel Covered with Rubber/Cloth, 36″ L: Amazon.com: Industrial & Scientific

Humboldt H-2087 Accuflame Gas Line for Bunsen Burners, Flexible Steel Covered with Rubber/Cloth, 36″ L from Cole-Parmer (coleparmer.com)