Vape Pens are rechargeable pen style e cigs. They are roughly the size of a thick fountain pen and based on the conventional eGo style. They have removable atomizers and a small tank for e-liquid.
Now the cheap models are likely to leak ejuice and you do have to be careful with safety. Most of the horror stories associated with e-cigarettes are those of the eGo style which have been used with the wrong charger or have been imported from China.
We strongly suggest if you are going to try this type of e cig, then use one of the better and more trustworthy brands as shown below.