The 9mm Steyr SPP (special purpose pistol) is a semi-auto only civilian version of the Steyr TMP (tactical machine pistol). The SPP is slightly longer than its burst-firing cousin, measuring 12 3/5" overall and tipping the scales at approximately 3.1 lbs with a fully loaded 15-round magazine in place. The entire outer envelope of the pistol is made of a synthetic material called DCEF 1313. The manufacturer reports that this substance is practically indestructible, having an expansion modulus similar to that of steel.

This outer envelope is divided into upper and lower receiver sections. The lower section houses several moving components - trigger and safety mechanism, for instance - while the upper section covers the bolt and barrel sub-assemblies. Incidentally, the box magazines for the SPP are made of the same extremely tough plastic material as that used in the AUG assault rifle and can be easily disassembled for cleaning. The SPP employs a rather ingenious delayed blowback, short recoil operation featuring a rotating barrel. This helps with delivering greater potential accuracy in rapid fire than a simple blowback pistol. The top of the upper receiver has a molded rail that allows the mounting of a variety of optronic sights. The pistols open sights however are found to be quite adequate for most of the uses that this gun is bound to encounter.