Tank

Tanks, or Cans (缶), are recovery items from the classic Mega Man games. Mega Man could stockpile and use these items to heal in an emergency. They first appeared in Mega Man 2 and appeared in most games since then, except for Mega Man 8, Mega Man & Bass, and some spin-offs.

Energy Tank
The Energy Tank, known as Energy Can (エネルギー缶) in Japan and in Mega Man 7, shortened to E Tank or E Can, first appeared in Mega Man 2, and since then in almost all games from the original Mega Man series. It fully recovers the health of the user. The maximum number of E Tanks that could be carried was initially four and was increased to nine for Mega Man 3 to Mega Man 6, but was reduced back to four for the Game Boy games and Mega Man 7. It returned to nine for Mega Man 9 and 10. The E Tank also appears in the Mega Man ZX series, where only one can be carried at a time.

One of the panels in Wily & Right's RockBoard: That's Paradise is a E Tank. In Mega Man: Battle & Chase, they are present in the endings of Mega Man, Proto Man and Guts Man. In the latter, Guts Man buys several E Tanks with the prize money, but he accidentally falls on them. In the game SNK vs. Capcom: Card Fighters DS, the Energy Can ("Can o' Energy" in the English version) is a Counter Card that restores 500 HP.

The E Tank also featured in Mega Man-related media like the Mega Man Megamix manga, the Rockman manga series, the Mega Man comic by Archie Comics, and the Mega Man animated series. In the latter, they are referred to as "Energy Cans", and given to Mega Man by Eddie when his energy is low. They are depicted as cylindrical green objects about the size of a soft drink-can, containing a glowing green liquid that can be drunk to recover lost energy quickly. Eddie can store up to five cans in his head.

Weapon Tank
The Weapon Tank recovers all the energy to one Special Weapon. Mega Man can only carry four of them at one time in most games, which is increased to nine in Mega Man 10.

The Weapon Tank makes a cameo appearance in Mega Man ZX, where only one can be carried at a time. Known as the W Tank, it is received by continually attacking the tangible doll in Prairie's room on the Guardian HQ airship. When used, it fully restores the Weapon Energy of all Biometals currently owned.

Super Tank
The Super Tank recovers all the energy from Mega Man's health and all weapons. Only one can be carried at a time.

Mystery Tank
The Mystery Tank, like the Super Tank, it recovers the energy from Mega Man's health and all weapons. If the M Tank is used when the health and all weapons are with full energy, it will turn all weak enemies on screen into extra lives, or give the player one extra life if no weak enemies are near. Also like the Super Tank, only one can be carried at a time. 

L Tank
L Tank is a Tank Proto Man gives to Mega Man before the fight against Dark Man 4 to recover all his energy. Performance-wise they are superior to E Tanks, but they were never mass-produced.

It also appears as an unusable ancient artifact in Mega Man ZX Advent found in the top left of Floating Ruins 1 after accepting Meg's request. Collecting this and the other 3 relics rewards the player with a Sub Tank.

It's unknown what the L from "L Tank" means, possibly standing for "Life Tank" or similar.

? Can
? Can (?缶), also known as Surprise Box, is a box with a question mark that appeared in Mega Man 3 and, once opened by Mega Man with a shot, gave him a random item like health and weapon energy.

Others

 * In Mega Man IV and Mega Man V, there are mini E Tanks that can't be used. After collecting four of them, they turn into a usable E Tank. They can be bought by 20 P Chips in Dr. Light's lab.
 * In RockBoard, Reggae drops an explosive pink Tank with a skull mark on it.

Mega Man E-Tank energy drink
The Mega Man E-Tank energy drink, known as Rockman E Can sports drink (ロックマンＥ缶飲料) in Japan, is an energy drink released by Capcom in August 2008 in Japan and in November 2009 in North America. As the name suggests, it's shaped like an E-Tank in Japan, but for unknown reasons, the visual was modified in North America. In March 2010, a new version with different flavor was released in Japan.



E Can Cushion
The E Can Cushion is a 30x30 cm cushion shaped like an E-Tank that was released on March 25, 2010 in Japan.

Rockcan Sound E Can
The Rockcan Sound E Can is a commemorative steel E Tank containing 10 CDs with music from the series.