My second TR250i came with Carbon Tech carbon fiber (CF) reeds installed. These reeds cause a much different intake sound than the original equipment (OE) reeds. The intake sound is much sharper and more aggressive. The power delivery is different too - more aggressive. I wanted both bikes to behave the same and preferred the OE reed behavior.
The OE reeds measure 38mm wide by 41.5mm long. The individual petal width is 18mm, and they are 0.37mm thick.
The Carbon Tech carbon fiber reeds measure 39mm wide by 41mm long. The individual petal width is 18.8mm, and they are 0.31mm thick.
SplatShop in the UK (one of my favorite vendors) sells reeds for TRS trials bikes. They measure 38.0 x 41.6 x 0.40mm, with an individual petal width of 18mm. I found them to work very well (to my liking, anyway). But if you are an aggressive rider, the CF reeds are worth a try.
One thing I did notice when changing to/from carbon fiber reeds is that it affects the idle speed. I had to adjust the TPS via K-Scan.
OE reed block, top view
OE reed block, side view
Chipped reed in need of replacement
Carbon Tech's carbon fiber Reeds
SplatShop's TRS reed
Left TRS reed, right Carbon Tech reed