There are four basic types of equipment and ninjas have a slot for each: band, suit, weapon and foot.
Second, very important, the quality from blue(worst) to red(best).
Third, level: 1,10,20,30 and recenly 40. Higher level means better, but ninja must reach that level to equip.
And fourth, but no lesser important, class type. Equiping wrong class gears gives half attributes.