A straight potentiometer type of motion transducer with a very light and stiff slider system especially made to facilitate attachment to biological objects is described. The transducer was originally developed for use in biological blast experiment for recording displacements of chest and abdominal walls diaphragm, and other body parts of laboratory animals in which experimental conditions, such as difficulties in attachment, large accelerations, and pressure and temperature gradients, make demands on the recording device which usually are not fulfilled by most other types of motion transducers. The weight of the slider system attached to the object is about 1 g but it can, if necessary easily be made as light as 0.1 g. The force necessary to overcome the friction of the slider contact is between 20 and 50 gram force. Recorded amplitudes have varied between 1 and 60 mm the recorded maximum velocity has been about 40 m/sec, and the maximum accelerations have been of the order of lO**4 g. Linearity and possible sources of error are discussed. Forskarrapport reprint