Welding and cutting machines, apparatus and equipment including torches; all the aforementioned goods including those that are gas-operated or electric; parts and fittings for the aforesaid including flash back arrestors; gas welding kits comprising hoses, regulators, blowpipes, welding attachments, and parts and fittings for such goods, including flash back arrestors; gas cutting kits comprising hoses, regulators, blowpipes, cutting attachments, and parts and fittings for such goods, including flash back arrestors; flash back arrestors; flash back arrestor used on hoses for welding or cutting torches