The Vindicator 21700 Mod with Constant Contact Switch by Kennedy Vapor.

PLEASE NOTE: This is a direct battery contact mechanical device and it is strictly for ADVANCED USERS ONLY! Be sure to check your atomizer's 510 connection when using it with this device. If your atomizer's positive pin in the center of the 510 connection does not protrude >1mm from the threads of the connection, your device may short. Use at your own risk! This mod does not have a locking mechanism, keep it away from children! Mechanical mods are an advanced user product and should not be used by anyone without the proper knowledge on your battery's amp limit and how to test your atomizer's resistance. Avoid using your device to the point where the batteries are completely discharged. Always double-check the resistance of your atomizer on an external ohmmeter, and ensure that your batteries are inserted with the positive pole facing the atomizer in order to prevent battery failure.