Beryllium oxide heat sink chips can be used to heat sink electrical leads or samples at low temperature with good electrical isolation. They can also be used as a buffer layer to take up expansion mismatch between an object with large expansion coefficient (e.g., copper, epoxy) and an object with a low expansion coefficient (e.g., a DT-670-SD diode sensor). One side is fully metallized with molybdenum/manganese, followed by nickel and gold. It is easily soldered with In/Ag solders. Sn/Pb solders can pull up metallization under some circumstances. The other side has two 1.27 mm (0.05 in) by 4.06 mm (0.16 in) electrically isolated solder pads. The thermal conductivity is several times that of copper in the liquid nitrogen region but about 1000 times lower at liquid helium temperature. The magnetic susceptibility is about that of nonmagnetic stainless steel.