Bruel-Kjaer - 4191 referenced MICROPHONE product produced by high technology. If you need other products from Bruel-Kjaer, please send us an inquiry by e-mail. We are one of the few companies which can present an offer for this product. Thanks to our large disturbiton network, we offer door delivery in most suitable conditions. 4191 referenced product is an original piece of your foundation or machine, original parts makes your machine live longer.