5/16"

Stainless Steel Short Blow Tubes for Deluxe Electric Mandrel Spinner. (shown on this page).  These are the blow tubes Scott uses in his Blown Vessel Tutorial Video. (also shown on this page by the Deluxe EMS).

 

These measure just under 4" long.  You don't need the extra length and weight when using the Deluxe EMS.

 

Yours will come to you bright and shiny and with no bead release on it.