| MODEL | UNION 2 | UNION 4 |
| Flash Power | 200 watts/sec | 400 watts/sec |
| Flash Control Range | 4.5 f-stops in 0.1 f-stop increments | |
| Power Requirement | 200~250V / 50~60Hz | |
| Flash Duration | 1/2050 | 1/2050 |
| Modelling Lamp | Halogen (Max 650W Optional) / 300W Standard Supplied | |
| Modelling Lamp Set-Up | Proportional / Full / Off During Flash / On all the Time | |
| Flash Colour Temperature | 5500 +/- 300K | |
| Recycling Time Min ~ Max | 0.1 ~ 1.7 sec | |
| Flash Ready Display | Audible & Visual | |
| Audible Recharge Confirmation | Yes | |
| Ready Light Indication | At 100% Charge | |
| Flash Triggering | Photocell / Sync Cable / Test Button | |
| Sync Socket | Yes | |
| Control System | Digital Panel, Digital Encoder | |
| Display System | LCD Display | |
| Flash Counter | Yes | |
| Settings Memory | Last Settings Retained | |
| Sync Voltage | AC 12V (Safe for Digital Cameras) | |
| Cooling Fan | Yes | |
| Stabilized Flash Voltage | +/- 1% | |
| Fuse Rating | 240V T10AL | |
| Over Heat Protection | Yes | |
| Reflector Mount | J Type Bayonet | |
| Stand Mount | Female | |
| Umbrella Mount | Yes | |
| Dimensions LxWxH (mm) | 390x120x115 | |
| Weight | 2.9 Kg | 3 Kg |