They take just about anything on top that you care to put on them. They have a 510 connection. Atomizers, cartomizers. tanks, RDAs, RBAs. Most people now are using RBAs as they are very adjustable to the user, pay for themselves over time and vape great. THe RM2 sold by Reosmods.com is a highly recommended rebuildable atomizer. Reosmods makes several mods in wood and metal and are renown for their extreme durability, ease of use, customer service, superior vaping quality and a friendly, helpful community.
Heres an example of a wood mod (maple door with wenge back) carrying 6 ml of juice and an 18650 battery with an RM2 rebuildable atomizer
and heres metal model with a Kick installed an an 18490 battery and a rebuildable atomizer.