RE: What is a tube call?
slee, as bad as this sounds unlubricated condoms work great. Also don't forget that Quaker Boy, Knight & Hale, and plenty of others sell latex for reeds. check out midwest turkey calls.
Also as a note Primos has a novel idea with the tube call they make. it has a snap on silicon reed instead of using latex & a rubber band. Just pop a new one on & away you go.