From the Manufacturer:

Nissin's MG8000 features extreme levels of creativity and professional performances. High heat resistance materials and quartz tube design reduce the heat effects significantly, emitting with full flash without overheating problems and achieving above 1000 times continuum. Assorting with Power Pack PS300 enables blazing fast and maximizes the performance extremely.

Features:

Extreme High Heat Resistance: World’s highest “Machine Gun” strobe, the high
heat resistance materials are developed for this unique model to achieve more than 1000 times continuum emitting with full flash power without overheating problems.

Equipped with flash diffuser: For full frame digital SLR camera, you can greatly expand the flash illumination angle and also weaken the shadow of the edge from direct flash lighting, suitable for portrait photography.

Using the latest quartz tube design: Capture the important moments, and reliably in
the extreme case of high power and high frequency flash shooting, without concerns about overheating flash effects.

Perfect combination: High-performance MG8000 with Nissin Power Pack PS300 can speed up the recycle time, perfectly to achieve high power and frequency of flash photography.

Auto Rotation & Color Display: The color display will automatically rotate from horizontal to vertical as the flash is rotated and the user friendly six icon interface represents each of the modes of operation– Auto, TTL, Manual/Av, Multi, Wireless TTL (Master/Remote) and Customer Setting.

External Service Box: External Power Pack Socket – MG8000 supports Nissin Power Pack PS300. X terminal – MG8000 has X-terminal socket for flash synchronization. USB Service Port – MG8000 provides a USB port to upgrade to the latest firmware.

Wireless TTL: The MG8000 Wireless TTL system supports Canon E -TTL/ E-TTL II, Nikon i-TTL and Sony ADI/P-TTL. MG8000 can be used in combination with Canon, Nikon or Sony original flash units as either Master or Remote (Slave).The MG8000 also supports digital (pre-flash system) and analogue (film type camera’s flash and/or studio flash under both of Manual and Av. priority mode.

Rear curtain sync and High speed shutter: In Rear curtain sync., the flash fires just before the rear curtain closes. By using this function at slow shutter speeds, a moving subject will appear with such moving marks behind. High speed sync. is recommended for daylight flash photography.

Using the latest quartz tube design: Capture the important moments, and reliably in the extreme case of high power and high frequency flash shooting, without concerns about overheating flash effects.

Perfect combination: High-performance MG8000 with Nissin Power Pack PS300 can speed up the recycle time, perfectly to achieve high power and frequency of flash photography.

Quick Loading Battery Magazine: The MG8000 has a battery magazine system which is the same as the Di866. A convenient battery magazine provides all four AA batteries load in the same direction, so that the batteries can be correctly inserted without fail even in the poor light condition.

My TTL: TTL exposure level is accurately calibrated for standard balance in accordance with Nissin’s standard. If any adjustment is however required, or if you like to set your own preferable level, it can be adjust for about ±3Ev. by every 1/3.

Calumet Speedlight Poweblock 900:

The Speedlight Powerblock 900 is the perfect power source for wedding and location photographers who rely on their speedlights for high volume flashes from a single charge, fast recycling, and consistent flash output. The extremely portable battery pack can conveniently clip onto your belt or be carried with the included shoulder strap.

The battery pack features a high-quality Ni-MH battery that will provide up to 500 full-power flashes from a single charge and will recycle most flashes in just 1 second. The Speedlight Powerblock 900 fully charges in 2 hours.

The cable is to connect the Calumet Powerblock 900 with the Nikon SB910, SB900, SB800, SB80DX, Nissin Di866/Di866 Mark II (Nikon dedicated model only) and other Speedlight models with the Nikon power port.

Usable camera: ETTL II and Nikon iTTL system

Guide No.: 60/198 at 105mm focal length (ISO 100 m/ft)

Wattage: 83 Ws. at full power

Illumination: 24-105mm (external diffuser)

Power source: 4 X LR6 batteries (Size AA Ni-MH or lithium batteries usable)

Battery life: 150-1500 flashes according to the mode (with alkaline batteries)

Energy saving: Stand-by mode in 30 seconds, and power off timer can be set

Recycle Timer: 5.5 seconds with fresh alkaline batteries for full power

Flash duration: 1/300 seconds (full power flash); 1/300-1/30,000 seconds (controlled flash)

Wireless flash: Wireless TTL off camera flash system (Master or Remote)

External Power: Nissin Power Pack PS300, Nikon original pack SD-8A / SD-9

Dimensions:148x78x127mm (5.8 x 3.1 x 5 inch)

Weight: 416g / 14.7oz (w/o battery)