Abstract: A flexible tube is sterilized and ready for coupling to sterile tubing in a sterile environment by steam sterilization in a closed environment in which steam pressure both inside and outside the flexible tube is the same. For this purpose, the flexible tube is coupled to a transfer cup which has door means sealingly attached at its mouth creating a chamber, which is openable when the coupling is to take place. An outlet from the transfer cup chamber thus defined allows sterilizing steam entering said chamber from the flexible tube with the door means in closed disposition to leave the transfer cup therethrough and flow around the exterior of the flexible tube at the same pressure as the steam within the tube. Once the flexible tube and transfer cup are sterilized, the flexible tube is coupled to the sterile tubing by admission of said tubing to the transfer cup chamber through the door means.