Slaveholders used both psychological coercion and physical violence to prevent slaves from disobeying their wishes. Often, the most efficient way to discipline slaves was to threaten to sell them. The lash, while the most common form of punishment, was effective but not efficient; whippings sometimes left slaves incapacitated or even dead. Slave masters also used punishment gear like neck braces, balls and chains, leg irons, and paddles with holes to produce blood blisters. Slaves lived in constant terror of both physical violence and separation from family and friends.