Stihl 4004-710-2180 PolyCut 5-3 PolyCut Head. The STIHL PolyCut is a multi- purpose cutting tool with three thermoplastic blades. Some models can also be fitted with flexible nylon line. It is ideal for lawn trimming or cutting close to walls and fences, around trees or between shrubs. The nylon line is particularly suitable for low grass. The thermoplastic blades can be used for mowing high-growing grass.