SG (Grease Ball Version)
Weight: 3.8g (including ball and grease)
Only compatible with Fortress Base
Has a long shaft with a Metal Ball inside - this results in relatively poor defense, relatively little movement, but passable stamina.
Takara version includes Grease (Silicone-Based) in a separate packet to apply to lubricate the ball, giving the SG its name. Hasbro do not include this, presumably for safety reasons.
Grease allows the ball to move more smoothly, making the behaviour more uniform and improving survival somewhat, the intended gimmick of the part - Hasbro lacking this, then, makes for a very curious situation.
Upper part which holds this cylinder has a platform that limits compatibility to Fortress Base and prevents the Metal Balls in the pockets of Fortress Base from escaping.
Canister lid has a long pole on the underside to push down on the ball, and a groove on the top prevents the canister section rotating inside the holder.
This overall acts as a less effective version of the Shielded Ball Bearings used by Zombies.
Were it compatible with a BB that had decent LAD, it would likely be a tier 2/3 option for Zombie customizations, based on testing using Twin Horn, Wide Survivor and SG (Grease Ball Version) with no Blade Base, the poor stability and inefficiency compared to bearing mechanisms is the primary limiting factor.
As it is, SG (Grease Ball Version) is entirely useless.