Be very careful of the Chinese dive lights on ebay.

[miketsp]

Most cheap china light you can't disassemble all the way due to the fact that they are "glued" together..
..snip..

I have to disagree with the use of the word "most". I bought 4 different types and was able to strip them all down completely and easily. On those that use an external circular ring with a magnet the internal sensor assembly generally has one blob of silicone to hold it at the correct orientation during assembly but once the head assembly is threaded into place that is what secures the internal parts.
I haven't seen any where glue is used as part of the structure.
For the prices I paid I was generally quite surprised by the quality of the individual parts.

 

[dfx]

I've had bad luck with this particular model (from the OP) as well - 2 out of 3 leaked. Seems to be a manufacturing problem. But I've also had great luck with other models of cheap Chinese lights. YMMV. Your best bet is to get several different models at the same time - some are bound to work great and you still save money over buying just one from a reputable manufacturer.

 

[sheeper]

i had 2 students (at different times and unknown to each other) who, of course, did not want to spend money on "good" dive lights that i suggested. they each purchased e-Bay Chinese lights. Student 1, first dive, 70 feet light was full of water. done. Student 2, 20 feet light was ok. next day at 60 feet light flickered then died...yup full of water. A third student got one of these lights but the lanyard clip broke on his first water entry. So we don't know if the light worked. it's probably still down there at 90 feet or so.

i tell students buy a good light once....buy a crap light at least twice.....in the end you'll buy the good light anyway