We just got in 2 new stone options and this is the first time we've offered a stone in a single flare!  Check out the single-flare Sodalite and Moss Agate. These are available from 8g to 5/8".  These are a great option for people who have trouble with double flares.  Plugs are flared on one side and come with o-ring to keep in place. 

The double-flare versions in Sodalite and Moss Agate are also awesome, starting at 3/4" and going up to 1-1/2" they have a concave design to keep them lightweight and comfortable even in the big sizes.