Force-Field Generation is the ability to generate energy barriers or bubbles of protective energy. User can create a shield, wall, barrier, dome, or a field formed from energy, elements, the environment, or by manipulating smaller items to form a greater whole. The shields typically take on a dome/spherical or flat shape centered on or around the user. Some users can generate a thin force-field around their body. Force-Field are capable to blocking/nullifying attacks (including physical attacks) or even reflecting them. Force-Fields are also used as containment to imprison others.
Force-fields aren't usually impenetrable and can be removed by energy drain or extreme force. Some users are also able to throw shields away from themselves or to catch things with them, while other users may be able to create them into any shape.
Vanya's sound-based energy can be shaped into protective barriers capable of absorbing intense amounts of force. During an alternate 1963, Vanya was able to shield herself from a Soviet tank round by projecting a barrier that was strong enough for the round to explode against harmlessly. She was additionally capable of causing a bullet to shatter harmlessly against a transparent barrier when she instinctively generated her energy due to one of the Swedes shooting at her at point blank range, which then burst out into a shockwave that repelled the assassin.
Lila was able to copy Vanya's power to absorb, redirect and focus sound and convert it into energy. She was able to create a force-field that held against Vanya's energy projection.