easiPart HD 18" [Heat Resistant Synthetic | Clip In] This one-piece volumizer, adds instant thickness and body, clipping in quickly for all-day comfort. The ultra natural feeling HD fiber can be styled with heat and parted in any direction. For extra volume and coverage, choose the new easiPart XL with a larger base construction. easiPart HD is available in various lengths: 8", 12" and 18"