A 7F is a short blade. Blade numbers run the opposite way to intuition — the higher the number the less coat is left — so this is the one for a close, tidy finish rather than a trim, and the F means full tooth, which gives a smoother result than a skip-tooth blade on a coat in decent condition.

This is Wahl's Prime Series, designed for the KM Supera Pet Clipper. Every Prime blade is precision ground from solid high-carbon steel, and the range is built around a quick change system so a blade clips and unclips for maintenance or replacement without tools. They are grooved to stay cool through longer grooming sessions, which is what keeps a blade comfortable when you are working through more than one dog. Because they are solid metal, they can be re-sharpened several times before replacement.

• Prime Series 7F blade for the KM Supera Pet Clipper
• Precision ground from solid high-carbon steel
• Quick change system, no tools needed
• Grooved to stay cool during long sessions
• Can be re-sharpened multiple times before replacement

A short blade leaves less between the clipper and the skin. That is the whole nature of a 7F — go carefully around folds, armpits, bellies and anywhere the skin moves, keep the blade flat rather than digging an edge in, and stop the moment it warms up. On some coats a blade this short is genuinely a bad idea: a double-coated dog clipped short does not grow back the same and loses the insulation the undercoat provides. Check the machine as well as the coat — this fits the KM Supera and is not universal.

Who it's for: groomers and experienced home users on a Wahl KM Supera who want a close, smooth finish.