Age-o-tonic Birthday Suits

Age-o-tonic Birthday Suits are devices which protect the user from unnatural aging, used to prevent KND operatives from being turned into adults by villain's aging devices. They consist of a small umbrella worn as a hat that creates a polygonal force field around the wearer.

Birthday suits first appeared in Operation: G.R.A.D.U.A.T.E.S., where the entire Kids Next Door Organization uses them during an attack on the Delightful Mansion From Down the Lane, assuming that the ray being used by Father is an aging ray. However, the actual effect of the ray is to turn the KND into animals, which the Birthday Suits offer no protection against. After the KND retreat to Kids Next Door Moonbase, Numbuh 202 of Sector G reconfigures the Birthday Suits to protect the wearer from the animal ray. Using these new suits, the remaining Kids Next Door attempt to return to Earth to defeat Father, but they end up only delaying the transformation for a few seconds.

In Operation: Z.E.R.O., Numbuh 2 modifies the Birthday Suits in order to provide resistance to Senior Citizombification. However, the enhancements are not yet complete when Numbuh 2 himself is turned into a zombie, and the Birthday Suits are only able to reverse the effects partially, returning half of Sector V's bodies to normal. Despite only half of their bodies looking normal, they are still in control of the zombified half. However, as Numbuh 2 stated, the zombie side is still evil, in such constantly kicking Numbuh 1.