M&M Smartek Dirt Blaster Rotary Nozzle K4–K7

A dirt blaster takes everything the pump delivers and puts it on a spot the size of a pencil, spun in a cone a few centimetres wide. On concrete, block paving and drains it is the fastest tool a domestic pressure washer has.

Where it must never go

Softwood decking, render, painted metal, lime mortar joints, car panels, window seals. Two seconds of hesitation leaves a mark that stays for years, and on render the water goes behind the finish rather than off it. The correct habit is simple: fit the rotary nozzle for hard mineral surfaces, and take it off before you clean anything else.

Third-party fittings

This is a pattern part for the Kärcher bayonet, at a fraction of the original’s price. Check the collar for drips the first time it is under pressure — a slight leak at a nozzle is never normal, and it means the seal is not seated.