Picatinny Rail

The P3 Mono Grip is a forward grip and monpod in one. It is designed to fit the Picatinny rail. So, what exactly is a Picatinny rail?

Picatinny Rail
The Picatinny rail or MIL-STD-1913 rail or STANAG 2324 rail is a bracket used on some firearms in order to provide a standardized mounting platform.

Picatinny Rail History
Its name comes from the Picatinny Arsenal in New Jersey, where it was originally tested and was used to distinguish it from other rail standards at the time. The rail comprises a series of ridges with a T-shaped cross-section interspersed with flat "spacing slots". Scopes et al. are mounted either by sliding them on from one end or the other; by means of a "rail-grabber" which is clamped to the rail with bolts, thumbscrews or levers; or onto the slots between the raised sections.

Picatinny Rail Uses
The rail was originally for scopes. However, once established, the use of the system was expanded to other accessories, such as tactical lights, night vision devices, laser sighting modules, reflex sights, fore grips, bipods, and bayonets. Because they were originally designed and used for telescopic sights, the rails were typically found only on the receivers of larger caliber rifles. But their use has extended to the point that today the combination of Picatinny rails and accessories are displacing the original iron sights in the design of many firearms, and they can now often be found on the undersides of frames and even on grips.

Picatinny Rail Technical Specifications
In order to provide a stable platform, the rail should not flex as the barrel heats and cools; this is the purpose of the spacing slots: they give the rail considerable room to expand and contract lengthwise without distorting its shape. The Picatinny locking slot width is 0.206 in (5.232 mm). The spacing of slot centers is 0.394 in (10.008 mm) and the slot depth is 0.118 in (2.997 mm).

Picatinny Rail info via Wikipedia.