The ET-S BDC is an upgrade version of ET BDC, it has an exterior metal sleeve surrounding the tank with two small windows that allow you to see how much liquid is left in the tank at all times.
Size: Φ14.5mm * 74.8mm
Weight: 27g / 5 piece Pack
Available resistance: 1.6Ω(3.0-4.2V), 1.8Ω(3.0-5.0v), 2.1Ω(3.0-6.0v)
Available Color: black,stainless,blue,yellow,green,purple,red,pink.