Plug to be inserted into ear canal for noise attenuation - has cylinder completely open at one end and contg. displaceable piston whose rod projects from other outer end for insertion into ear

摘要

The car plug is designed to be inserted into the ear canal and has an an oval cross sectional shape. It can also be elastically deformed and the major axis of cross section has a length of between 6 and 15mm. The minor axis has aa length of between 3 and 10mm. Centrally through the ear plug is a tube (11) which is open at both ends. It can be connected to a sound transmitter.