No depolariser, so it will only deliver a constant current of around 10mA for long periods. As well it will dry out, and is in no way leakproof. However if you use a small tyvek bag to hold the MnO2 and graphite, and use some steel plate as a current collector plate with a zinc plate anode each side of the plates in contact. Place in a plastic box and add electrolyte and it likely will run a clock for a decade or more if you seal the top with wax and have a small porous ceramic plug for pressure relief.