I work in Saudi Arabia a lot in the oilfields. The sands get into everything no matter what!!! You have to keep your drip tip covered or you'll be spitting sand. I use a SID indoors and an ego when I am out and about working. I was using a protank II mini but switched to a 19mm Ibtanked set up. The cartos last longer than kanger coils. The glass is pretty thick and you dont have to break your connection to fill. Sand destroys everything in time. The 15mm has thinner glass and doesnt hold much. Hope this helps.....