Because the person intubating must be blind up until the time at which the tube is to be used, the unopened envelope will be taken to a third anesthesia provider, who will prepare the ETT with stylet in an area that is not visible to the person performing the intubation or to the person timing the intubation. The person performing the intubation will specify what size of tube they wish to use. This will most commonly be 7.5 mm internal diameter (ID) for a female and 8.0 ID for males, but the operator is free to use whatever size they feel is appropriate. The tube size selection will take place before unblinding so the group allocation cannot affect the decision of tube size.