Husqvarna 255-4t Grass Blade for Brush Cutter 578443701 525LS 525LST 323R

What It Is

This is a genuine OEM Husqvarna grass blade (part #578443701) designed for use with Husqvarna brush cutters and trimmers, specifically for cutting heavy grass, weeds, and light brush. It replaces the standard trimmer head on compatible models to provide a cleaner, more efficient cut in dense vegetation.

Fitment & Compatibility

Before buying, confirm your machine is a Husqvarna model from the following list: 525LS, 525LST, 323R, or any brush cutter that accepts a 255-4T blade system. The blade has a 25.4mm arbor hole (center hole) and a 4-tooth design—measure your existing blade’s center hole to verify. This is an OEM part, so it’s a direct fit for these models; aftermarket alternatives may require different adapters. Check your owner’s manual or the part number on your current blade (578443701) to ensure compatibility. Do not use on trimmers with a smaller arbor size (e.g., 20mm or 25mm) without the correct adapter kit.

Key Things to Know

• Installation requires a blade adapter/retaining nut – This blade does not attach directly to the trimmer head; you’ll need the Husqvarna blade adapter kit (often sold separately) and a retaining nut. If you’re switching from a trimmer line head, you’ll need to remove it and install the adapter.
• Sharpening and replacement – The blade can be sharpened, but it’s a wear item. Replace when cutting edges are rounded or chipped. Expect to replace every 1-2 seasons with moderate use.
• Safety note – Always wear eye and leg protection. Brush cutter blades can throw debris. Never use on a machine rated below 25cc or without a blade guard.
• Torque spec – Tighten the retaining nut to 20–25 Nm (15–18 ft-lb). Over-tightening can damage the blade or shaft.

Should You Buy It

Buy this if you have a compatible Husqvarna brush cutter (525LS, 525LST, or 323R) and need a durable, OEM blade for cutting tall grass, weeds, or light brush. It’s a reliable upgrade over trimmer line for heavy-duty clearing but requires the correct adapter and safety gear. Avoid if you only trim light grass or have a smaller trimmer model.