The Cell Keys resemble mostly keys for lever-type locks. They have a flat, hexagon-shaped white bow with a red rim and a symbol resembling the Eggman Empire's on it. They also possess a short shaft and two teeth for a head. They are usually found afloat on the ground.
The Cell Keys are found exclusively in Team Chaotix's version of Final Fortress where ten of them can be found hidden in the Stage. In the normal Mission for the Final Fortress, the objective is to collect only five Cell Keys, while in the Stage's Extra Mission, all ten must be collected.
When touching a Cell Key, they will give off a small "ping" and then slowly fade away. In most cases, they are found in cages that the player must unlock, usually by destroying surrounding enemies.
Cell Keys locations
Cell Key #1
Hit the gong switch at the start and grind the electrified rail. At the end, the player will land on a platform with two Egg Pawns. Destroy them to release Cell Key.
Cell Key #2
After the first checkpoint, Hit the Power Gong to get to the narrrow hallway, then Triangle Jump across to the other side. Once the player is on the new path, run down past the laser beams and ride the Jump Plate. After that, destroy the Heavy-Egg Hammer to release the Cell Key.
Cell Key #3
When the player reaches a deactivated Pole encaced into a Fan section, use the Cannon on the section before it to destroy the unbreakable containers below the fan, in order to find the switch that activates the Fan. After that, use the Fan to glide up to the highest point and onto the platform with the Cell Key on it.
Cell Key #4
At the top of the section before the Detonator Switch is a E-2000R. Destroy it and the door will open revealing the Cell Key and Check Point.
Cell Key #5
After the second checkpoint and crossing the electrified rails, is another E-2000R. Defeat this one and the Cell Key will be unlocked.
Cell Key #6
When the player comes to a wide area with six cannons and a Heavy-Egg Hammer. Defeat the foe to release the gong switch. Then Hit the gong switch to land on a ledge, then use the Ramp to land on another electrified rail. At the end of the grind, defeat the E- 2000R and two Egg Pawns with shields to release the Cell Key.
Cell Key #7
After that, when the player gets to the top section, two Heavy-Egg Hammers will drop down. Use Team Blast to get rid of them. Get the Cell, then touch the Check Point. After the Check Point, use the Warp Flower.
Cell Key #8
When the player emerges from the Warp Flower, jump onto the platform and destroy everything around the playable characters. In the center is the Cell Key.
Cell Key #9
Hit the Gong on the front of the previous key to run to the collapsible path on the right, and fly over to the narrow hallway. Triangle Jump quickly after landing to grab a 1up. Upon reaching the spiked ball, land and then run before the platforms fall. Switch to Charmy and fly up to the Egg pawn. Destroy the foe to get the Cell key.
Cell Key #10
Warp from the Warp Flower at the end of the previous key, then after warping from the flower, the player will be in the top portion of a corridor. Ahead is a laser barrier and a Egg Knight. When the enemy is at a high point, bounce off it and then Triangle Jump to the other end over the barrier. Grind the electrified rail and then land on the center platform where the final Cell Key is locked up. To get the last Cell Key, the player will need to work for it. The player must defeat a Heavy-Egg Hammer on the two ledges to the right and left, and the one on the U-shaped ledge to get the final Cell Key.
Although Eggman has told Chaotix that will need those keys in order to open his prison cell, in the final scene in Team Chaotix's story, Vector was punching the cell's door down instead of using the keys.
↑Sonic Heroes: Prima's Official Strategy Guide pg. 131