The Wahl Universal Stainless Steel Comb in Size 8 leaves the coat 25mm (2.5cm). This fits on all brands of A5 blades on both size 10 and size 30 blades, but do check the blade and clipper guide below before you buy. Stainless steel combs are recommended for all coats including difficult coats (thicker, double, mixed texture, curly etc) for a more secure fit than plastic combs. You can also get this size comb as part of the  for coat lengths from 3mm to over 2.5cm. 

More details below