Arm Band on Glove hand of pitcher

[Rich Ives]

OBR from the MLBUM

2.13 WRISTBANDS
No player is permitted to wear white wrist bands or bandages because of the difficulty in
discerning the white of the baseball and the white of the wrist band. Colored bands are permitted,
but a white band with a colored stripe is still considered a white band and is prohibited.

Also:

2.10 PLAYERS WEARING GOLF GLOVES
A pitcher is not allowed to wear a golf glove while pitching. Other defensive players may wear a
golf glove on their glove hand but they shall not rub the ball with the golf glove on their hand.