Accordingly, slide-in system 310 described herein, including the systems and methods for inserting the sensor and connecting the electronics unit to the mounting unit, enables the mounting unit 316/electronics unit 314 subassembly to have a volume of less than about 10 cm3, more preferably less than about 8 cm3, and even more preferably less than about 6 cm3, 5 cm3, or 4 cm3 or less.