Microsurgical Curved Castro Needle Holder, Diamond Dusted, 18 cm (7") Microsurgical Curved Castro Needle Holder, Diamond Dusted, 18 cm (7") 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 x Category Dealer PartnersSales RepresentativeStrategic MarketsSchools RepresentativeAccutron™ Equipment Sales Zip Code Find RepresentativeReset Select a category, input a zip code and click on Find Representative, or explore the complete list here.