Box type pistons also have their pin bosses moved inward toward the center of the piston, but include an additional rib to strengthen the deck of the piston and pin bosses. These too allow the use of shorter wristpins which promotes reduced wrist pin deflection. The box structure actually creates a “box” around the small end of the connecting rod. These pistons are not always lighter, but are typically stronger than traditional round style pistons and typical X- Forgings

The most common type of forgings and have the side relief machined into the piston versus having it forged like the forgings below. Since machining the side relief takes place, it allows flexibility for different styles depending on the application and final weight of the design. The bottom band can be left on for use of buttons, or it can be machined off to remove weight or help large stroke engines that come out of the cylinder at BDC.

X-Forgings are designed to minimize friction and reduce weight without compromising strength. They have the side of the piston forged and their pin bosses moved inward toward the center, allowing the use of a shorter wristpin. With the use of different strut angles and bracing, an X-Forging is configured by adjusting the weight balance between high and low stress areas.