For use with the EGO Power Head System 15'' String Trimmer Attachment STA1500 only. The number 1 customer complaint with any string trimmer is line replacement. EGO has taken this pain point away with the new EGO 15 in. Rapid Reload replacement trimmer head to quickly and easily load new cutting line. The 15 in. cutting swath, bump-head line advancement and professional-grade 0.095 in. cutting line make quick word of yard clean ups. Replace a string trimmer head immediately If the head loosens after it is fixed in position. A string trimmer should never be used with a cracked or malfunctioning head. Replace a cracked, damaged or worn-out cutting head immediately, even if damage is limited to superficial cracks, because all such attachments may shatter at high speed and cause serious or fatal injury.EGO parts are designed specifically for your EGO POWER+ Power Head System and offer the highest quality, performance and value.