The EHPro Penny mod is a fantastic 100% copper mod. Copper provides excellent conductivity, which means less voltage drop and more voltage to your coils. The positive pin is adjustable via a screw on the bottom of the top cap. It can also adjust to accommodate your 18650 battery, so everything will fit flush and have solid contact points. It is 510 threaded only. The switch is slightly recessed, and won't fire when set down. There's a threaded locking ring for extra safety when in a pocket or bag. The body is one solid tube, and only accepts IMR 18650 cells. The EHPro Penny mod is a solid device for any vaper. Remember, a Penny vaped is a Penny earned!