Microsurgical Curved Castro Needle Holder, Diamond Dusted, 18 cm (7") Microsurgical Curved Castro Needle Holder, Diamond Dusted, 18 cm (7") Sign in to save to your list NHDCPV Fine-tipped Microsurgical Needle Holders are used to grasp and guide the needle when suturing. Recommended suture sizes: 6-0, 7-0, 8-0. Where to Buy Ask a specialist