Designed for use with: - Z - 2994 Series Castroviejo Corneal Transplant Trephine - Z - 2995 Universal Trephine Handle - Z - 2997 Universal Trephine Handle with Cottingham Punch. Overall length: 9mm, 0.4 inches. Available in .25mm increment sizes from 6.00mm to 9.50mm. When ordering, please specify size (example Z - 2996 6.00).