Abstract: A wellbore logging device incorporating selected electronic sensors and a power source is sealingly and removably embeddable within an instrumentation recess formed in a new or existing downhole equipment component such as a downhole tool or other component of a bottomhole assembly (BHA) in a tubular string such as a drill string. The logging device may be a modular device comprising an electronics module incorporating the electronic components, and a power module incorporating one or more energy cells. The electronics module and power module are engageable to form the logging device for insertion into an instrumentation recess, and to enable energization of the sensors and data transfer between the modules. In alternative embodiments, the logging device is a unitary device incorporating both the electronic components and the energy cells.