I carry 3.
Joye 510 standard size manuals (2) w/ Boge cartomizers and NoSmokeVA.com's roomy 510 PCC
KR808D-1 (Vapor4Life, Volt) standard size manuals (2) with cartomizers
(2 assembled cigs and the spare batteries and cartos for both are in the 510 PCC since a KR8 batetry will fit in the non-charging slot)
Plus a charged Riva 510 750mah battery in a Chinese cloth-covered lipstick case (wrapped around the middle so the button cannot touch the inner sides of the case). That is my battery backup or just if I want bigger hits.
Plus 3-5 small bottles of
juice. And it all fits in a 7x7 inch woven cross-shoulder pouch.
But if I am just running to the grocery store (rather than to work or to the inlaws) then I just stick a complete 510 manual with carto and a complete KR8 manual with carto in my jeans pocket. I like to alternate 2 contrasting flavors to keep the flavor fresh and that's how I do it - 2 ecigs.
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If you want a suggestion for just one - SmokelessImage Volt with manual batteries - totally sealed end on the manuals and a very small recessed button that should not get accidentally pressed even in tight jeans. Or for longer trips, a 3.7v box mod with on/off switch. Both used with cartomizers.