 This provided more stiffness but maintained the flexibility and the slippery surface.Other differences were the length (the new introducer was , which is much longer than the gum elastic bougie) and the presence of a 35° curved tip that let it be steered around obstacles.The concept of using a stylet for replacing or exchanging orotracheal tubes was introduced by Finucane and Kupshik in 1978, using a central venous catheter.