Interface: USB+PS/2
Model No.: PERIPRO-302
Part No.: W310
USB ID: VID_09DA&PID_0006
Product Name: USB Optical Mouse
Year: 2009
Perixx's attempt to make a clone of Kensington Expert Mouse #64325, quickly discontinued due to minor flaws that lead to the poor reviews. Overall the design is almost identical, except for the scrolling mechanism: instead of ring, PERIPRO-302 uses common wheel located above the ball - as in Kensington Expert Mouse Pro. Glossy finish and loud click sound resemble Kensington SlimBlade.
Sensor is 800 cpi Elan OM02 with red illumination LED, the microcontroller used is an epoxy blob on PCB, so there's no any marking - but USB VendrID it reports belong to the A-Four Tech company. Most likely, A4Tech is actual OEM maker of this trackball. Switches under main buttons (marked DS) are rectangular, switch under wheel is square. Encoder is mechanical. Scrollwheel is made of clear plastic, and have transparent silicone "tire": looks like it's designed to be illuminated, but in this case it's not. Quality of casing plastic parts is very good. Ball is not freely-laying as in Kensington models, but is easily removable for cleaning by unscrewing retaining bezel.
The ball is of the same 57mm size as in Expert Mouse Pro or earlier Turbo/Expert models (slightly larger than latest Expert Mouse 55mm one), and does not have special coating to help the tracking. Surface of the ball is dull: don't know if it's a result of wear, or it was specifically treated at the factory. It is supported by 3.0mm steel beads, positioned a bit too widely. It's always difficult in such design to select proper spacing: if they're too close, the movement of the ball will be easy but it will be prone to rocking, while putting them too wide will make the ball stable but the movement will be hard. In this case, the support diameter is 95% of ball size, while for example in Kensington Expert it's 88%. Despite absence of any specific coating, old OM02 sensor tracks it just fine. Moreover, it tracks even translucent Expert Pro ball almost flawlessly! There's some online reviews claiming the original ball was coated, but in my case there's no any traces of that. Available pictures also show just black ball.
Funny thing is, the ball size was specified by Perixx as 55mm: it was noted in all the product pages and repeated by resellers - but in fact it's a standard 21/4" ball. Don't know if it was never-corrected mistype, or result of rounding-down the imperial size recalculated to millimeters to the nearest half-centimeter value.
As received, the movement of ball was essentially blocked due to its rough surface and heavily worn steel beads. I've replaced them with 3.175mm Zirconia ceramic ones, and swapped the ball with custom Kensington nacre "Earth-like" one: movement become smooth and easy, tracking is still reliable.
Perixx product catalogue from 2009:
https://trackballs.eu/media/Perixx/Prod ... 2-2009.pdf
Manufacturer's original and contemporary logos:
In general this trackball is good and convenient: if higher-quality support beads and patterned ball were used by the maker initially, it had all the chances to become serious competitor to Kensington. Traditionally, it was used to prepare this article.