Metal tubing, in particular of steel; penstock pipes of steel for the transport of petroleum and/or natural gas; junctions of metal for pipes, in particular of steel, in particular for oil pipelines or gas pipelines; gas-tight thread coupling of metal, in particular of steel, in particular for oil pipelines or gas pipelines; pipe muffs of metal, in particular of steel; threaded pipes of metal, in particular of steel; manifolds of metal for pipelines; pipe strings of metal for the extraction of petroleum and natural gas; oilfield pipes of metal; drill strings of metal for oil and gas fields

Installation of threaded pipes and/or gas-tight thread couplings of metal; repair and maintenance of threaded pipes and/or gas-tight thread couplings of metal