400/600/800/1000 dpi sensitivity, switchable while working and without driver needed.
Markings inside suggest that other mice from serie (X-708 to X-718) share same parts.
Steel 23 g weight (with X-708 mark).
It's little disappointing that only main switches (left and right button) are from OMRON.
Middle mouse button comes from Trantek Electronics.
After few years of usage both OMRON switches work flawlessly, but TTC switch had some problems as it was started to generate double clicks each time. Few drops of cleaning agent helped. Be careful and make sure it is dried before disassembling because mouse wheel (transparent plastic element) is not resistant to organic solvents.
Second problem (very common) comes from rotary mechanical switch that causes weird jumps when scrolling. Again, cleaning with organic solvents eliminates the problem (but it reappears after about 6 months, so this is not permanent solution). On the plus side mouse is easy to open and reassemble (no latches) so cleaning is quite fast. Petroleum jelly may work too and probably is safer to use.
Omron D2FC-F-7N are working reliably for me. In case of problem nice thing is they are serviceable: http://www.overclockers.com/forums/showthread.php?t=594646.
Optical sensor: Agilent ADNS-3060. According to datasheet it has selectable 400dpi / 800 dpi resolution, so I would suppose that other resolutions (including highest 1000 dpi) are interpolated. It seems to be common practice and some newer A4Tech mice (X-705, X-755, X-760, AK-47) share same sensor and their resolutions from 1000 dpi do 2000 dpi are interpolated.
It seems that X-718 and X-710 share same PCB, so some modding may be possible. "Upgrading" to X-718 would require either some simple PCB modification or - much more difficult because used MCU is not popular among amateurs/hobbyists - changing firmware or EEPROM data. Since even X-710 highest resolution already is interpolated it would give no real benefits in my opinion - it would give no more than changing mouse sensitivity in software. It would give one additional sensitivity setting (X-718 has 5 settings vs 4 settings in X-710), but if anyone actually using this feature that could also add more confusion when cycling through settings to go back to initial dpi. In my opinion two or three sensitivity settings would be optimal.
Most likely EEPROM is used to store selected by user dpi setting - I wonder if settings are stored each time they are changed by user what could cause problems with EEPROM life time.
This mouse worked for me for almost 10 years which is really impressive but finally mechanical mouse wheel encoder degraded to the point that cleaning it wasn't helping and I've damaged it when trying to disassemble it and bend contacts. There are some cheap replacements on ebay but I'm not sure if their quality would be satisfying. One I swapped from cheap, brand new no-name mouse was basically no better than old one from A4tech (generating pulses in reverse direction from time to time).
Second point of failure is cable. This is definitely good quality cable - thin, flexible and it needed repairing maybe once during ten years but in the end it started dropping outer isolation like molting snake. Pretty weird.