The EFC library has several pictures of the different models next to each other. Id say having heald both the 801 and 901, that the 901 is probably more what she might be into, the 801 is a little thicker, although it is longer. the 901 is about 9.5 mm in diameter, somewhere between a standard 'king' and a camel wide. the 801 is more like a large pen/small marker. I am currently switching from the 901 as my primary to the kr808d-1. using the 901 atty as a dripper. perhaps you might want to look into the longer batterys for the kr8, such as the vapor king model that vapor4life carries, it will fit both the cartomizers for ease of use on the go, and the 901 atty for dripping pourposes. also, the whistle tips for the 901 fit the kr8 cartomizers as long as you cut them down a little. they are snug enough to let danglle from my eeth without falling out, but not difficult to get in and out.