I'll agree for the most part with r77r7r. It would be helpful to know what size battery device you will be putting a cartotank on to give better suggestions.
Basically a tank is just a juice reservoir for a cartomizer. Expections are to hold the juice without leaking, and to stay on the cartomizer and not inadvertantly fall off and empty its juice contents. Nearly all tanks can accomplish these minimal expectations, except perhaps the cheaper tanks. Cheaper tanks may have poorly fitting parts or poor fitting o-rings, which prevent them from accomplishing those minimal expections. I never recommend a tank that costs less than $20 for that reason, based on my earlier experiences with cheap tanks.
I've not found a need for the so-called locking tanks. A decent quality tank with properly fitting o-rings is not going to leak juice or inadvertantly fall off of the cartomizer. I'm also not a fan of the juice fill hole tanks. They usually require a needle and syringe to add juice; I personally would prefer not using those tools to fill a tank. I find it just as simple and fast to use a tank tool and just slide the carto down the tank and drop juice between the top cap.
My recommendation for a beginner's cartotank would be either the Pro DCT cartotank kit from My Vapor Store for $22.50 or the IBTanked pyrex cartotank kit for around $25.
View attachment 225439 510 Pro DCTank Combo
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