Endotracheal Safety Flex Reinforced Tube Size 6.0 x 10 The Mallinckrodt Safety-Flex endotracheal tube is a reinforced endotracheal tube cuffed without murphy eye. The endotracheal tube has a large volume low pressure cuff with a satin slip surface inside tube. The Mallinckrodt Safety-Flex endotracheal tube comes with a 15mm connector PVC and has a 8mm inner diameter.