The price shown is for one 510 drip tip.
This is a small, translucent resin drip, with a simple and straightforward design.  Its clean lines, however, do look very nice on many atomisers.
The following measurements are provided so that you can check compatibility with your atomiser:
Specs w/dimensions in mm (approx.)
MaterialResin
O-rings2
Overall length17.5
Max. diameter9.8
Base length5.4
Base diameter8.5
Min. bore4.3
Please note that every drip tip is not guaranteed to fit every atomiser perfectly due to slightly different manufacturing tolerances.  Incompatibilities can normally be easily resolved by fitting different o-rings - a kit is available as eBay item 281770683745  (just type the item number into the eBay Search box).
Since I started vaping in August 2012, I am proud to say that I have not touched any tobacco products. I consider myself an experienced vaper, currently using a range of mechanical and electronic mods with various Genisis, sub-ohm tank and dripping atomisers. I also mix/prepare my own e-liquids.
Please contact me if you have any questions. I will do my utmost to resolve any issues to your satisfaction. Items are individually wrapped and posted in genuine Jiffy packaging, with machine-printed address labels.
There are more vaping items in my AtomiserDripTips eBay shop
Note to eBay: This is not a smoking or tobacco product.
The U.S. F.D.A. have not approved the use of e-cigarette products, but they have no banned them.  Even if they do, their jurisdiction does not extend to the U.K. 
The U.K. Health Act 2006, Chapter 28, Part 1, Chapter 1 states that “smoking” refers to smoking tobacco or anything which contains  tobacco, or smoking any other substance, and smoking includes being in possession of lit tobacco or of anything lit  which contains tobacco, or being in possession of any other lit substance in a form in which it could be smoked. 
E-Cigarettes do not produce smoke, and they are not classified as tobacco or smoking products in the U.K.