| Features | BK1 | BK2 | BK3 | BK4 |
| Description | Magnetic door contact | Transmitter with 2 inputs | Transmitter with 3 inputs | Transmitter with 3 inputs and magnetic door contact |
| Compatible receivers | P16, P32, P64, EXT116s, EXT11, KM25 | P16, P32, P64, EXT116s, EXT11, KM25 | P16, P32, P64, EXT116s, EXT11, KM25 | P16, P32, P64, EXT116s, EXT11, KM25 |
| Operating frequency | 868 MHz | 868 MHz | 868 MHz | 868 MHz |
| Communication range in building | Up to 100m | Up to 100m | Up to 100m | Up to 100m |
| Communication with hopping code | Selectable | Selectable | Selectable | Selectable |
| 2-way technology | Yes | Yes | Yes | Yes |
| Contact Open transmission | Yes | Yes | Yes | Yes |
| Contact Close transmission | Yes | Yes | Yes | Yes |
| Tamper transmission | Yes | Yes | Yes | Yes |
| Battery low status transmission | Yes | Yes | Yes | Yes |
| Supervision transmission | Selectable (every 1h for Grade 1, Custom; every 20 min for Grade 2 ) | |||
| In-built magnetic contact | Yes | - | Yes | |
| In-built inputs for external detectors | - | 2 | 3 | 3 |
| External detector = magnetic contact | - | - | Yes | Yes |
| External detector = roller type detector | - | - | Yes | Yes |
| In-built output to power the external detector | - | Yes (up to 20uA) | - | - |
| Unique ID number for magnetic contact | Yes | Yes | - | Yes |
| Unique ID number for every in-built input | - | Yes | Yes | Yes |
| Power supply | BK1 - ½ AA, 3.6V or CR2 3V BK1vP - CR123A | ½ AA, 3.6V or CR2 3V | ½ AA, 3.6V or CR2 3V | ½ AA, 3.6V or CR2 3V |
| Battery life | BK1 ~ 3 years BK1vP ~ 5 years | ~ 2 years | ~ 2 years | ~ 2 years |
| White color model | BK1 | BK2 | BK3 | BK4 |
| Brown color model | BK1_br | BK2_br | BK3_br | BK4_br |
| Overall dimensions W x H x L in mm | 27 x 23.6 x 75 | 27 x 23.6 x 75 | 27 x 23.6 x 75 | 27 x 23.6 x 75 |
| Operating humidity | 0% - 70% | 0% - 70% | 0% - 70% | 0% - 70% |
| Operating temperature | -5oC up to +50oC | -5oC up to +50oC | -5oC up to +50oC | -5oC up to +50oC |
| Production status | In production | In production | In production | In production |
| Latest firmware version | v.2.002 | v.2.002 | v.2.002 | v.2.002 |
| Wiring manual | ||||