I bought this as I was aware that it had a point where I could attach a lanyard and the size (gig) was big enough so I wouldn't have to upgrade for a while.
At the back of the flash drive it had two very tiny gaps where I just about managed to thread a small key ring through and I used this to connect to my lanyard. If the holes were bigger it would have been much more convenient, but either way it worked and served its purpose.
The retractable USB was very useful as there are no lids/tops to lose or forget about. However the USB isn't completely covered and this can leave it exposed to a bit of dirt. But as long as you don't take it out in the middle of a sandstorm or rugby match, it should be okay.
I've read a few reviews on this pen where people criticised the 'flimsy plastic' but again, as long as your not planning on throwing the pen around or dropping it repeatedly on solid concrete it'll be fine.
It has a light that flashes once it is inserted into a computer and the true size is 29.8 gig after formatting.
Overall the price and practicability of this USB pen can't be beaten, thanks again Play.com.