They're both WMO, they're not 1.1a's...

same mouse...
it have model name 1.1a and name wheel mouse optical (aka wmo).

what's changed from standard wmo to 1.1a?

1.1a oem
1.1 retail.

isnt it backwards ? #1 confused me =(

i'm just trying to figure out what mine is. It says "Wheel Mouse Optical USB and PS/2 Compatible" on the bottom of it. No 1.1 or 1.1A.

Was there ever a wmo 1.0? if so, what did they change in the 1.1 version.

wmo 1.0 is überold and skips really fast. If you happen to find one for sale, it's been dug out of some 1950's antinuke shelter.

wmo 1.1 and 1.1a are the same, the " a " only tells us it's the oem version. I don't think any high school director would go out to the supermarket and buy 50 wmo....So I believe it's really the oem one.
Some 1.1 don't say anything on the sticker, but if it skips really fast, burn down that 1.0.

Then there the intellimouse 1.1 ( or something like that, not sure about it's name ) which causes the most " wtf are you talking about I don't have side buttons on my wmo " moments.

Wait there's different versions of the WMO? What's the differences between them?

I have "Wheel Mouse Optical USB and PS/2 Compatible", purchased from recycling vendor in 2011. I can't see 1.1(a) anywhere. On net user reports that they can overclock their WMO 1.1(a) to 1000Hz easily. Mine i can reach only 200Hz on USB port (i checked it on few systems - windows, linux, and two motherboards). I think this is a difference. Be careful and chose 1.1(a). Negative acceleration at 125-200Hz is really annoying. Overclock to 500Hz is a necessity on this mouse.

I have both and sensor for sure is the same but they're a bit different ( or it's placeboo?). I mean mice skatez for sure are different, and in 1.1a my scrollwheel was fucked up after 1 month and about other version i'm playing on it longer than 2 years and scroll is still fine ( maybe a bit noisy but nothing more )

search google for: D66-00069

please guys please dont talk if you dont know anything!
1.1 and 1.1a are the same mouse just one of them is oem one of them is the retail one. but nooo! difference. the sensor the shape the cover everthing is same. and there are 2 mouses with this sensor(actually 3 but we dont tank ablout 3.0) wheel mouse optical and intellimouse(with side buttons). and their only shape is different.

but 1.0 is totally different thing! never buy it or sell it. it is like olllld shitty mouses. as crc said if you search for d66-00069 you will find the right mouse.

and if you want to compra it with another mouse please look this sensor: STMicroelectronics OS MLT 04.
thanks

I once used 1.0 (basic) it was terrible... skipped like hell if you swinged it fast beyond a certain point.