That's exactly what they are ~ but what's great about them is you can use them to lower the nic (and the cost) without any decrease in flavor.
Tasty Vapor sells liquid in 30ml bottles at $15.00 per bottle ~ $10.00 if you choose their flavor of the week, which changes every Friday. If you order 48mg strength and you also
buy a 4oz doubler of the same flavor and mix the two bottles together you wind up with 5 times the amount of
juice with a nic level of 9.6mg at a cost of $30.00 (or $25.00 if you go with the flavor of the week).
Here's a link to TV's FAQ -
http://www.tastyvapor.us/faq-i-15.html
Scroll down about half-way and there's a breakdown of how much doubler you need to mix with the liquid to achieve the mg you prefer.