The wearer of an arrow catching shield can activate or deactivate the property with a command word.
An arrow catching shield grants the wielder an additional level of defense against ranged attacks. Also, any projectile or thrown weapon that passes within 5 feet of the wearer bends in its flight path and targets the wearer instead. (This does not hold true if the wearer is under total cover relative to the attacker, or if the projectile or thrown weapon has a higher enhancement bonus than the shield in question.)
The latter effect does have a downside, however. Though they may not do damage, diverted ranged attacks are far more likely to hit an activated arrow catching shield.