Compression fields were a type of technology used to fit large objects into small spaces though miniaturisation. It was similar in use and capability with molecular nanoscaler technology. Miniscopes used compression fields to keep specimens inside them miniaturised. Specimens extracted from the field resumed their original size. (TV: Carnival of Monsters) One of the Slitheen's compression fields was acquired by Henry van Statten and kept in the Vault. (TV: Dalek) The Teselecta used a compression field to miniaturise its crew to the size of an insect. (TV: Let's Kill Hitler)