AN AUTO-RELEASE FIRING DEVICE FOR ATTACHING TO GUNS THAT CONTAIN EXPLOSIVES FOR PERFORATING A WELL. IT IS USED TO PERFORATE A WELLBORE AND SIMULTANEOUSLY RELEASE GUNS INTO A RATHOLE. THE FIRING DEVICE IS IN THE FORM OF A HOLLOW, SEAMLESS TUBE MADE OF COLD ROLLED CARBON STEEL WITH A CEV OF 0.36 TO 0.41. IT HAS NO OTHER MECHANICAL FEATURES. IT IS USED TO IGNITE THE EXPLOSIVES USING WEIGHTED IMPACT AND IS ACTIVATED BY JARRING OR DROPPING A WEIGHTED BAR OR PRESSURE RELEASE ON THE TOOL STRING. THE TUBE IS AVAILABLE WITH THREE SIZES, HAVING AN OUTER DIAMETER OF 74.17 MM, 85.7 MM OR 108 MM AND A LENGTH OF 0.61 M. THE TUBE IS THREADED.

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 7304 FOR TUBES, PIPES AND HOLLOW PROFILES, SEAMLESS, OF IRON (OTHER THAN CAST IRON) OR STEEL GIR 6 HAS BEEN USED TO CLASSIFY THE GOODS TO SUBHEADING LEVEL 7304 29 FOR CASING, TUBING AND DRILL PIPE, OF A KIND USED IN DRILLING FOR OIL OR GAS: OTHER THAN DRILL PIPE: OTHER THAN OF STAINLESS STEEL CN CODE 730429 10 FOR OF AN EXTERNAL DIAMETER NOT EXCEEDING 168,3 MM TARIC 73042910 20 FOR OF CIRCULAR CROSS-SECTION, OF AN EXTERNAL DIAMETER NOT EXCEEDING 406,4 MM AND WITH A CARBON EQUIVALENT VALUE (CEV) NOT EXCEEDING 0,86 ACCORDING TO THE INTERNATIONAL INSTITUTE OF WELDING (IIW) FORMULA AND CHEMICAL ANALYSIS ALSO CLASSIFIED IN ACCORDANCE WITH:- NOTE 3 TO SECTION XV NOTE 1(D) TO CHAPTER 72 HARMONISED SYSTEM EXPLANATORY NOTES (HSEN) GENERAL NOTE (1) TO CHAPTER 73 AND TO HEADING 7304 COMBINED NOMENCLATURE EXPLANATORY NOTES CNEN TO HEADING 7304