How is this different from a swing check valve?

It uses a spring-loaded ball instead of a hinged disc, so it closes quickly and quietly and works in any orientation. Swing checks are simpler and cheaper but can slam and need gravity to seat.

What is cracking pressure and why does 1/2 psi matter?

Cracking pressure is the upstream pressure needed to open the valve. At 1/2 psi it opens on very low flow, which suits low-pressure lines and pump discharge where a stiffer spring would stall flow.

Yes, up to 125 psig saturated steam at 350°F. The PTFE ball and stainless internals are rated for that service; keep within the cold working pressure of 400 psig for non-shock water.

Does it work in any mounting position?

Yes. The spring closes the ball regardless of orientation, so it can be installed horizontally or vertically. Match the flow arrow on the body to the direction of flow.

What is included in the box?

The valve itself. It has female NPT threads on both ends, so you supply the mating pipe nipples or fittings and thread sealant.

The retainer and guide unscrew to reach the ball and spring, so worn seats can be serviced. Check the specification sheet for the exact part numbers before ordering spares.