What could one theoretically do with this buck/boost driver?

[rainst0rm]

Found this driver on ebay. Is this viable for a high-output diode?

24mm Boost/Buck 3-18V 3 Modes Circuit for 3or4 XML Driver - 30W

This circuit has low voltage protection at 5.7V, so please use two or more li-ion for best result.
Input Voltage: 3-18V (recommend use of 2-4pcs 4.2V 18650 or 4-6pcs 3V CR123A)
Output current (single LED): 5A
Output current (3 or 4 XM-L LED wired in serial): 3A
Modes: Low - Medium -- Height

Low voltage Protection: When using single or two Li-ion batteries, when input voltage drop below 5.7V, LED will flash twice per 3 seconds and then turn off after 3 minutes.
Over-heat Protection: When internal temperature becomes too hot, driver will automatically ramp down its brightness, make sure you "heat-sinked" the driver.
LED power output: single LED (8-10W), three or four LED wired in serial (25-30W)

Input requirement: Input current is about 3-3.5A, make sure the wiring and switch is capable of handling this type of high current.
*When driving 3 or 4 XML (serial) with 1-2 li-ion (serial), this circuit acts as boost circuit. When using 3-4 lion wired in serial, this circuit becomes a buck and temperature regulated circuit.

Dimensions:
Battery board measures 26mm
Main driver measures 24mm
Total height measures 17mm

rain

 

[Cyparagon]

The regulation is pretty terrible if it varies from 3 to 5A depending on load. Even if it wasn't, you'd need to drop the current for most diodes out there. That would involve replacing the current sense resistor... if there is one.

 

[Wolfman29]

That doesn't look like it's a boost driver at all, either. Just buck.