Collars in Biothane Collars in Biothane: Biothane is a synthetic leather substitute.   Soft to the touch, resistant to traction and wear, flexible.   It does not absorb water.   It does not require maintenance.   Unassailable by mold, bacteria and odors.   It is easy to wash with warm water and soap.   Biothane maintains its characteristics even at low temperatures. Mister Wolf uses original Biothane U.S.A.