High performance at the push of a button

The Steambow PowerUnit is a pneumatic quick release system for the Excalibur Micro 355, Bulldog 400 and Bulldog 440. The same system is also used with the Steambow Onyx, which was specially developed for the PowerUnit.

The quick release system is powered by compressed air, stored in small and light pressure bottles, as they are common and proven in the paintball sport for decades.

The Steambow system is very robust and easy to use. A main valve regulates the cocking process, everything else (like manual safety or trigger) remains unchanged.

In the cocked state, the limbs are in exactly the same position as on the respective ground-arm crossbow. All performance data, such as arrow speed, precision, etc., therefore apply unchanged to a Steambow as well.

The PowerUnit also allows even the most powerful recurve crossbow to be folded into a convenient format.

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Excalibur Micro 355 (355 fps)

Excellent quality

Watch the PowerUnit in action

Effortless cocking, near tool-less maintenance, substantially increased safety, collapsible limbs for easy transport: the Steambow PowerUnit pneumatic cocking system has it all.

  • Silent cocking

    You can cock the limbs almost silently within one second. When you relax the limbs after firing, a quiet hissing can be heard as the air escapes.


    High rate of fire

    The string is hooked into the latch with the limbs relaxed, the next bolt is loaded, and the Steambow is ready to be cocked and fired.


    Enhanced safety

    You decide when to cock the limbs, ideally just before firing. This precludes many dangerous situations.

  • Collapsible for easier transport

    You can use the quick-release pins to fold the limbs alongside the mainframe in seconds. This makes the crossbow narrow enough to fit easily in a normal bag.


    Safe loaded storage

    A Steambow can be stored and transported with a loaded bolt at zero risk of discharge. The optional disposable CO2 cartridges also allow a Steambow to be made ready in seconds after being stored for years.



    The automatic cocking function allows you to cock the Steambow without effort in any orientation and position, including in tight tree stands.

  • Tool-free string replacement

    The limbs of a conventional crossbow are under great tension even when the bow is not cocked. The string cannot be removed from the limbs without special tools or jigs. With a Steambow, you need no tools whatsoever to replace the string.


    Always ready to go

    Even if your air tank is empty, you have no compressor or backup tank, and you have used your last CO2 cartridge – you can also cock your Steambow manually with the right accessories.

  • Precision Manufacturing

    Made of high-quality aluminum alloys on state-of-the-art CNC machines. All surfaces are hard anodized with a matte finish. This ensures high performance and a long life.


    Longer Life

    The limbs of a conventional crossbow are always under tension and can lose their strength over time, especially when exposed to high temperatures. As the limbs of a Steambow are under no tension until pressure is applied, this risk is eliminated.

How a Steambow works

  • Transport configuration

    The limbs are folded to the mainframe. The Steambow fits snugly in a bag, can be stowed away to save space, or carried easily with a shoulder strap.

  • Steambow uncocked

    Since the string isn't taut, it can easily be fitted in the lock. In this position, the Steambow is absolutely safe, since at this point there is no tension in the limbs and string.

  • Ready to shoot

    At the push of a button, the Steambow is silently tensioned and is now ready to fire.

Technical data

3,35 kg
72 cm
25,4 cm
Effective range
120 m
Draw weight
280 lbs / 127 kg
Bolt speed
355 fps / 108 m/s

Specifications for use with the Excalibur Micro 355



FAQ - frequently asked questions

Here you will find many helpful answers, tips and tricks about our products.


Here you can find the manuals for our products.