| 《 Engineering manual 》 |
| Techfill Engineering Manual-HB Analogue-V2a |
| Techfill Engineering Manual-HB Digital-V2a |
| Techfill Engineering Manual-Digital Inverter-V1b |
| Techfill Engineering Manual-NiCd Battery-V1a |
| Techfill Engineering Manual-Vented Lead Acid Battery-V1a |
| Techfill Engineering Manual-VRLA Battery-V1a |
