This is a Federal Shotshell known as the Grand Slam chambered in 12 Gauge 3.5", model PFCX139F6.
Extend the range and enhance the lethality of lead turkey payloads with Federal Premium(R) Grand Slam(R). Its FLITECONTROL FLEX(TM) wad system works in both standard and ported turkey chokes" opening from the rear for a controlled release of the payload and extremely consistent patterns. The high-quality copper-plated lead pellets are cushioned with an advanced buffering compound to provide dense patterns and ample energy to crush gobblers.
Features:
12 Gauge
1,200 Feet per second
#6 Copper-plated lead shot
10 Rounds per box
3-1/2 Inch shotshell