It seems that rather than actually specifying a wheel diameter, this is simply repeating the wheel type - polyurethane bogie (rather than single) wheels.
Teli seems to be the Finnish for bogie (or boggie in Swedish).

Compare various links in relation to the SILVERSTONE 6615-1150 model:

SE - GAFFELLYFTVAGN SILVERSTONE 6615-1150 2500KG BOGGIE PU
• Hjul: Boggie, PU
https://www.ahlsell.se/10/forvaring--hantering/lyft--hanteri...
FI - HAARUKKAVAUNU 6615-1150 2500KG TELI PU
https://www.ahlsell.fi/34/tyokalut-ja-teollisuustuotteet/sai...
EN - 6615-900/1150
Steering Wheels - PU
Load wheels - Bogie PU
Polyurethane wheel = PU
(Table on page 4)
[See also the table on page 38 for platform trolleys, heading Wheel Diameter (mm / type), with entries 100 / solid / PU]
http://donar.messe.de/exhibitor/cemat/2016/S752914/silversto...

Teli (engl. bogie tai am.engl. truck)
https://fi.wikipedia.org/wiki/Teli
A bogie (/ˈboʊɡi/ BOH-ghee) (in some senses called a truck in North American English) is a chassis or framework carrying wheels, attached to a vehicle, thus serving as a modular subassembly of wheels and axles.
https://en.wikipedia.org/wiki/Bogie

Similar UK site

Pallet trucks
Single wheels or bogie wheels?
Single wheels are preferable on smooth floors and are also easier to turn with. These wheels are however subjected to wear. Bogie wheels work better on even floors. As the load is distributed over several wheels, individual wear is reduced (less load, less friction). Climbing wheels facilitate long-side handling of pallets.
http://www.gigant.co.uk/products/warehouse-transportation/pa...