Goodman Games

Because rings for medium creatures are diminutive items I've classified them as taking up space 3 sizes smaller than the mech they are built into. So rings for gargantuan and smaller mechs take 1 space, colossal 2, and so on. Since magic used on a mech doesn't automatically affect the crew some rings are not really usable: Blinking, Invisibility, etc. A ring of Chameleon Power can make a smaller mech fairly stealthy, and even larger mechs can benefit from its ability to disguise itself as similar sized & shaped mechs and monsters. Rings of Climbing, Jumping, Freedom of Movement, Swimming, and Water Walking all improve a mech's mobility. there are a number of rings that can improve a mech's defenses. A ring of Counterspells or Spell Turningcan prevent a devastating spell like Disintegrate or Rusting Grasp. Rings of Energy Resistance or Evasion if your mech has a good Ref save are useful against foes with area effects. Rings of Protection or Force Shield are really only useful for smaller mechs that still have a reasonable starting AC.