Perfecter

The Perfecter (パーフェクター) is one of the two transformation gears for Kamen Rider X, attached to the right side of his Ridol belt, with the Redizer on the left. For the first 27 episodes (and later in Kamen Rider Taisen), Keisuke Jin used the phrase "Set Up" (セタップ) and jumps into the air with his bodysuit manifesting as he removes the Redizer and Perfecter from the sides of his belt to form his helmet and then snap up the faceplate to complete the transformation.

From 28 onward, Keisuke uses the phrase "Dai Henshin" (大変身) to transform while making a "X" sign with his arms after being powered up by the Mercury Circuit.

Apollo Geist
Revived Apollo Geist is equipped with a Perfecter on his helmet following his first defeat by X-Rider. Likewise, the alternate Apollo Geist from the World of X-Rider, Guy, was revived by the Government of Darkness after being killed by that world's X-Rider. This A.R version has the ability to take the life force of other people to augment someone else as Guy (and Tsukasa on one occasion) frequently demonstrated.

Electro-Wave Human Tackle
In World of Stronger, Yuriko Misaki has a Perfecter to protect her head and her face, giving her helmet a more Rider-like appearance.