the sensor 142 to extend outside of the structural shell to fluidly communicate with formation fluids however the sensor 142 may be covered with a cap 146 as shown in fig2 4 and 6 the cap 146 is generally cylindrical and may comprise stainless steel or other materials the cap 146 may exhibit an end hole 148 providing for fluid communication between the inside and outside of the cap 146 to the sensor 142 the cap 146 may also include a lateral through hole 150 extending all the way through opposite sides of the cap 146 as shown in fig2 3 the through hole 150 may provide for fluid communication to the sensor 142 the through hole 150 may comprise an access port to fill the wire bonds between the sensor 142 and ceramic printed circuit board 104 with insulative material the cap 146 may also comprise a bellow type structure not shown and a protective nose or cap not shown to protect the sensor 142 from the formation fluids the chamber defined by the bellow type structure and the metal cap structural shell may then be filled with silicone oil or a similar fluid to transmit the pressure of the formation fluids to the sensor element 142 for example a pressure sensor the bellow type structure may be electron beam eb welded to the stainless steel material of the cylindrical cap 146 other types of protective barriers also may be provided to protect the sensor 142 from the formation fluids u s patent application ser no ______ titled protective barriers for small devices with inventors harrison et al filed concurrently herewith and having common ownership describes other protective barriers.