Auveco AVC10050 0.25 in. 20 TPI Screw Extruded U-Nut – Phosphate. AUVECO 10050 Extruded U-Nut 1/4 in – 20 TPI Screw Phosphate. Engineered with durability and ease of use in mind it ensures efficiency and long-lasting results for both professionals and hobbyists.Features.