A tougher blade that is suitable for mowing rougher grass, weeds, bracken and bramble and over rough ground where there may be stones etc that would damage a finer blade.
When peened it will also neatly cut finer grasses and soft weeds – a multi-purpose blade.
The best length of Ditch blade depends on the size of area you want to mow and the number of obstacles to mow around. A 65cm blade gives you more “bite forward” and allows you to mow more with each stroke, whilst still being versatile enough for trimming around obstacles etc.
A shorter blade is better in more confined areas. It exerts less leverage on the snath, so causing less stress on the snath when mowing tougher vegetation. If you want a shorter ditch blade have a look at the Falci 187 Short Ditch blade, which comes in 55cm and 40cm lengths
All new blades should have the lacquer cleaned off the cutting edge to prevent it clogging the sharpening stone. See this post for further details.