After decades of success with traditional hammer-fired DA/SA pistols, SIG SAUER is jumping into the world of striker-fired hanguns with a completely new design that’s also modular — and multi-caliber. But why the mysterious blue box? . . .

Because the P320 is so new that it hasn’t officially been announced yet. There are no photos of it, but SIG has leaked plenty of other details in advance of the official launch at the SHOT Show. Until then, here’s what we do know:

Striker-fired like a GLOCK or Springfield XD.

Serialized fire-control group like the not-too-successful P250.

Modular frame and slide/barrel assemblies in Subcompact, Compact, and Full sizes.

Available in 9mm, .357 SIG, .40 and .45 ACP with double-stack magazine capacities the same as the P250.

SIGLITE night sights are standard.

MSRP: $713 for a complete pistol; additional frame kits and caliber conversion kits will be extra.

We’re still waiting for a lot of other details, though:

Will it use P250 magazines? The P250 mags are already made in the same calibers and sizes as the 320 will be offered in, and they’re already out there on the market. Magazine commonality would be a nice change from SIG’s tradition of reinventing the wheel for every new pistol.

Did SIG lower the bore height from the (let’s face it) too-darned-tall P22x series?

We’ll get the answers next week, hopefully along with a sample gun to play with. Stay tuned.