OO / 1:76 / 4mm. For OO Scale Model Railway Layouts. This kit has been created to savour what existed during the World War II era. 1 x Police Station Decal Accent Kit. SCALE COMPATIBILITY: OO / 4mm. INSTRUCTIONS FOR USE: All of our decal kits need to be assembled, but before this can be done the decals will need to be carefully removed from the sheet by cutting them away one by one with a craft knife, scalpel or fine scissors.