The following, to be employed in the exploration, discovery, development, maintenance, testing, depletion or production of oil or natural gas wells or potash or rock salt deposits: Flanged casing heads; Screwed casing heads for surface casings of an external diameter exceeding 273 mm, or rated for service in working pressures exceeding 14 MPa W.O.G. (water, oil, gas)

Live horses, asses, mules and hinnies. > The following, to be employed in the exploration, discovery, development, maintenance, testing, depletion or production of oil or natural gas wells or potash or rock salt deposits: Flanged casing heads; Screwed casing heads for surface casings of an external diameter exceeding 273 mm, or rated for service in working pressures exceeding 14 MPa W.O.G. (water, oil, gas) > The following, to be employed in the exploration, discovery, development, maintenance, testing, depletion or production of oil or natural gas wells or potash or rock salt deposits: Flanged casing heads; Screwed casing heads for surface casings of an external diameter exceeding 273 mm, or rated for service in working pressures exceeding 14 MPa W.O.G. (water, oil, gas)