A HALF INCH MICROPHONE CAPSULE FOR ELECTRO ACOUSTIC SENSORS. THEY DO NOT COMPRISE A COMPLETE WORKING SYSTEM THEMSELVES AND MUST BE COMBINED WITH PRE AMPLIFIERS. THIS SUB ASSEMBLY THEN FORMS PART OF A COMPLETE SOUND LEVEL METER OR SIMILAR PRODUCT. THE CAPSULES ARE CONSTRUCTED FROM HIGH ALLOYED STAINLESS STEEL, AND THE DESIGN INCORPORATES AN ALL METAL , HIGHLY TENSIONED SENSING DIAPHRAGM AND A QUAZI PERMANENT ELECTROSTATICALLY CHARGED FLUOROPOLYMER COATING UPON ONE INTERNAL PART TO PROVIDE PRE-POLARISATION , ELIMINATING THE REQUIREMENT FOR A POLARISING SUPPLY BY THE PREAMPLIFIER. IT HAS A SINGLE SENSING ELEMENT COMPRISING OF A METAL DIAPHRAGM SUSPENDED OVER A SOLID METAL BACK PLATE, FORMING TWO ELECTRODES OF A CAPACITOR. IT TRANDUCES ACOUSTIC INTO ELECTRICAL ENERGY.

CLASSIFICATION HAS BEEN DETERMINED IN ACCORDANCE WITH THE FOLLOWING:- GENERAL INTERPRETATIVE RULES (GIR)S GIR 1 HAS BEEN USED TO CLASSIFY THIS PRODUCT BY THE TERMS OF HEADING: 8518 MICROPHONES AND STANDS THEREFOR; LOUDSPEAKERS, WHETHER OR NOT MOUNTED IN THEIR ENCLOSURES; HEADPHONES AND EARPHONES, WHETHER OR NOT COMBINED WITH A MICROPHONE, AND SETS CONSISTING OF A MICROPHONE AND ONE OR MORE LOUDSPEAKERS; AUDIO-FREQUENCY ELECTRIC AMPLIFIERS; ELECTRIC SOUND AMPLIFIER SETS. GIR 6 HAS BEEN USED TO CLASSIFY THE GOODS TO SUBHEADING LEVEL 851890 PARTS. CN CODE 85189000 OTHER THAN ELSEWHERE SPECIFIED IN THIS HEADING. TARIC CODE 8518900099 OTHER THAN ELSEWHERE SPECIFIED. ALSO CLASSIFIED IN ACCORDANCE WITH: HSEN RE 851890 REFERS, PARTS NOTE 2(b) TO SECTION XVI REFERS