The connector is the same but... I connected my SP4 Core m Charger to my SP3 and left it overnight, not intentionally just not thinking about it, the connector is the same. In the AM the SP3 was 50% charged which is probably about where it was when I connected it. I needed to charge the SP4 so moved the cable over... charging light did not come on... not charging... unplugged the charging brick from the mains and plugged back in... now the Charging light is on and charging. Based on this one time event I would recommend not using a SP4 core m charger on other Surface Pro devices. Note: The design and specs on the charger are different than the other chargers as well. Output voltage is 15V vs 12V.