This project acquires a pool of thirty-five seismic instruments designed to operate in the deep field in extreme cold, down to minus 55 degrees centigrade. These seismometers will be used to make winter measurements in various field experiments in the Antarctic and Arctic. In terms of intellectual merit, observations made by these devices will help us understand and model ice sheet behavior in response to global warming and improve our view of the earth from crust to core. In terms of broader impacts, this project represents new, never before available research infrastructure. The instruments will be acquired and managed by IRIS, the university consortium for seismology, and will be made available to the general scientific community for polar work. The instruments will see immediate use for US flagship projects during the International Polar Year (2007-2009).