| 1/00 | Details |
| 1/02 | Details Incandescent bodies |
| 1/04 | Details Incandescent bodies characterised by the material thereof |
| 1/06 | Details Incandescent bodies characterised by the material thereof Carbon bodies |
| 1/08 | Details Incandescent bodies characterised by the material thereof Metallic bodies |
| 1/10 | Details Incandescent bodies characterised by the material thereof Bodies of metal or carbon combined with other substance |
| 1/12 | Details Incandescent bodies characterised by the material thereof Bodies which are non-conductive when cold, e.g. for Nernst lamp |
| 1/14 | Details Incandescent bodies characterised by the shape |
| 1/16 | Details Incandescent bodies Electric connection thereto |
| 1/18 | Details Mountings or supports for the incandescent body |
| 1/20 | Details Mountings or supports for the incandescent body characterised by the material thereof |
| 1/22 | Details Mountings or supports for the incandescent body Lamp stems (seals for leading conductors therethrough H01K 1/38) |
| 1/24 | Details Mountings or supports for the incandescent body Mounts for lamps with connections at opposite ends, e.g. for tubular lamp |
| 1/26 | Details Screens; Filters (associated with envelope H01K 1/28) |
| 1/28 | Details Envelopes; Vessels |
| 1/30 | Details Envelopes; Vessels incorporating lenses |
| 1/32 | Details Envelopes; Vessels provided with coatings on the walls; Vessels or coatings thereon characterised by the material thereof |
| 1/34 | Details Envelopes; Vessels Double-wall vessels |
| 1/36 | Details Seals between parts of vessel, e.g. between stem and envelope |
| 1/38 | Details Seals for leading-in conductors |