HIPA Replacement Air Filter 4140 124 2800 for STIHL FS38 FS45 FS46 FS55 KM55 HL45 HS45 FC55 Edger String Trimmer Replacement manufacturer part number: 4140 124 2800 Fits STIHL String Trimmers - FS38, FS45, FS46, FS55, and KM55 STIHL Hedge Trimmer - HL45 and HS45 STIHL Edger - FC55 Qty: 5 piece