force on the sides 127 128 of the package 100 the seals 112 also are compressed when the nut bolt interface 109 is tightened the seals 112 between the feedthrus 102 and package body 110 provide a hermetic interface at all temperatures from cryogenic to above room temperature fig5 and 6 also show a plurality of mounting bolts 113 and nuts 114 for use in mounting the package 100 and the integrated circuits onto thermal straps or rails or other external surfaces as shown in fig4 the body 110 and lid 111 contain a plurality of thru holes 120 for the mounting bolts 113 the thru holes 120 and the mounting bolts 113 allow for mounting and tight bonding of the package 100 and integrated circuit 101 to a cooling strap or rail without creating any tensile or shearing stress on the package which could cause failure of the package and integrated circuit at extreme temperatures the embodiment of fig5 and 6 also includes a plurality of fastener inserts 106 on a side 129 of the package 100 for use in mounting peripheral electronics and hardware in the preferred embodiment the fastener inserts 106 vary in size including 4 40 6 32 8 32 and 10 24 the fastener inserts may be included on more than one side of the package 100 a further embodiment of the present invention is shown in fig7 and 8 which is a package 100 that provides heat transfer through direct conduction without active fluid flow in this embodiment the package 100 is made from sic or c u2014 sic material that is thermally matched to the integrated circuits or emitter arrays the top surface 125 of the package 100 contains patterns of electrical traces 130 with contact pads 135 and metal.