Item box

Item Boxes or Monitors as they were known as and still known as today appear as television sets with an icon on the screen, sometimes these monitors have static. Since Sonic Adventure they had a redesign to look more like glass capsules with the icon picture inside.

Classic Power Ups
Super Rings icon would be a gold ring and gives the player 10 rings. In later series different variety of Ring Power Ups were added with a number witth the icon to tell how many rings will be added like 1, 5, 10 or 20. ? would mean random.

Invincability icon would be sparkles in early game but mroe of a rainbow pattern later in the series. Grants the player immunity from damage and destroys opponents on contact. It's only temporary lasting roughly 30 seconds.

Shield icon would be a green or blue bubble that would ofcourse incase the playing character in such barrier and protects the player from a damage. afterwards it will disperse.

High Speed or Power Sneakers icon would be of Sonic's shoe and increase the speed of the player for roughly 30 seconds.

1up icon would be a mugshot of playing character (example Sonic) and will grant the player another chance if he looses (Gets hurt without any rings, crushed or fall down below the level).

Their have been other different types of Power Up's throughout the series, some specificly to certain games, but listed above are the usual Power Up found in all games.