Options:
Firefly 2 Slave unit | Firefly 3 Slave Unit

Both the Firefly 2 and Firefly 3 are based on a slave unit designs by David Gibson of the BCRA CREG, UK site2.caves.org.uk/flash

Firefly 2 Operation
Just plug the slave unit into your flashgun and you are ready to shoot!
If you do not want to use the illumination from the trigger flashgun (the one connected to the camera) then you can tape the infra red filter provided to the window of the trigger flashgun to provide an infra red only flash. The slave unit will be triggered, but no visible light will come from the trigger flashgun.

Firefly 2 Slave Unit Specifications
 Compact & Light
Dimensions - 60 x 40 x 19 mm.
Weighs only 60g.
Range
At least 10m in the studio, 500m in near-dark conditions.
Triggering
Infrared and visible light sensitive. New: Infra-red filter now included to make your own infra-red trigger flash gun.
No Misfires
Non-sensitive to torches or lamps if used at night.
Connection
Internal terminal block for ease of connection to the device of your choice or for connector replacement e.g. hot shoe adaptor.

Worry Free
No on/off switch - the unit is permanently switched on so you cannot forget to switch it off!
Economical
Battery life over two years from a single CR2032 coin cell or equivalent (included). (After June 2009)
Battery life over a year from three LR43 "watch" batteries or equivalent (included). (Prior to June 2009)
Outdoors
Easy to waterproof.
Fitting
Heavy-duty hook and loop fastener included to attach the unit to the flash gun.
Guarantee
Guaranteed against manufacturing defects for two years.

Firefly 3 Operation
This slave unit is designed for use with digital cameras that produce multiple flashes before taking a picture (pre-flashes)
Just plug the slave unit into your flashgun and you are almost ready to shoot! Most digital cameras work first time with the default settings of the Firefly 3. In other cases you can use the learning feature of this unit to train for your camera's unique sequence of flashes. Once learnt the attached flashgun will go off on the last flash each time for a perfect shot.
If you do not want to use the illumination from the camera flashgun, to avoid "misty" pictures, then you can tape the infra red filter provided to the camera flash window to provide an infra red only flash. The slave unit will be triggered, but no visible light will come from the trigger flashgun.

Firefly 3 Slave Unit Specifications

 Top
Compact & Light
Dimensions - 60 x 40 x 19 mm.
Weighs only 70g.

Range
At least 10m in the studio, 500m in near-dark conditions.
Triggering
Infrared and visible light sensitive. New: Infra-red filter now included to make your own infra-red trigger flash gun.
Can be re-triggered 5 seconds after a previous trigger.
Ignores pre-flashes used for focus, metering and red-eye reduction
No Misfires
Non-sensitive to torches or lamps if used at night.
Connection
Internal terminal block for ease of connection to the device of your choice or for connector replacement e.g. hot shoe adaptor.
Worry Free
No on/off switch - the unit is permanently switched on so you cannot forget to switch it off!
Economical
Battery life over two years from a single CR2032 coin cell or equivalent (included). (After June 2009 - Green/Black Label)
Battery life over a year from three silver oxide SR44 "watch" batteries or equivalent (included). (Prior to June 2009 - Yellow/Black Label)
Outdoors
Easy to waterproof.
Fitting
Heavy-duty hook and loop fastener included to attach the unit to the flash gun.
Guarantee
Guaranteed against manufacturing defects for two years.