A 5-in-1 blade is one blade doing the work of five, and for anyone who does not want a drawer full of them that is the entire argument. A lever on the side steps the cutting length through its range, so you change length mid-groom rather than changing blade.

This is the standard Arco blade: 46mm wide, cutting from 0.7 to 3mm across the adjustment range. It is precision ground from stainless steel, and it snaps on and off without tools, which makes cleaning it a matter of seconds rather than a job. Wahl are direct about one thing worth knowing: these blades are classed as disposable and cannot be sharpened.

• 46mm blade width
• Cutting length 0.7 to 3mm via a 5-in-1 adjustment
• Precision ground stainless steel
• Snaps on and off for cleaning
• Classed as disposable — cannot be sharpened

It is a consumable, and that changes the arithmetic. Wahl's Prime blades are solid metal and can be sharpened several times; this one cannot, so when it dulls it gets replaced. That is a fair trade for the adjustability, but it is worth knowing before you compare prices with a blade that lasts years. Practically: brush the hair out after every dog, keep it oiled, and stop the moment it warms up, because a hot blade burns skin faster than most people expect — and a blade running at 0.7mm has very little between it and the dog.

Who it's for: Arco owners who would rather adjust one blade than own five, and home groomers doing a couple of dogs rather than a salon's worth.