They are adjustable for all scales according to the adverts.
"It is versatile in another way too – While it comes pre-set for 16.5mm or OO/HO track, we include in the pack full sets of spacers for 9mm/N/009/HOe, 12mm/TT, HOm, HO Narrow gauge. OO, HO and ON30… even EM and P4 users are not forgotten either, as we included a set of spacers that works for both!"
https://www.dccconcepts.com/product-category/specialised-model-accessories/dccconcepts-rolling-roads/