The 10-49mm insulation includes all insulation thicknesses within this range. Helps you easily find the insulation sizes you, for example, the common sizes in this category include:

12mm, 20mm, 25mm, 30mm, 32.5mm, 37.5mm, 40mm

Brands that offer these sizes include:

Celotex, Kingspan, Isover, Rockwool, TLX and Knauf