A one way valve for a biological flow passage includes an elongated braided structure sized for insertion in the biological flow passage, a portion of the braided structure forming a substantially tubular shell, the braided structure maintaining an expanded operative shape after being deformed to a small dimension; a non-porous coating of the braided structure; a constricted portion of the elongated braided structure disposed between a proximal end and a distal end thereof, the constricted portion closing off a channel of the braided structure and defining at least one funnel shaped region of the braided structure to prevent flow towards the distal end; at least one hole formed in the non-porous coating, permitting a flow of one of air and fluid towards the proximal end; and an anchoring portion to retain the one way valve in a selected location within the biological flow passage.