The thickest and thinnest cytoskeleton fibres are
microtubules and microfilaments respectively
microfilaments and intermediate filaments respectively
intermediate filament and microtubules respectively
myosin filament and microfilament respectively
The microtubules are the thickest filament of the cytoskeleton having diameter of 25 nm with 15nm lumen.
The microfilaments are the thinnest filament of the cytoskeleton having a diameter of 7 nm.