Cross-Bolts – 1/4-28 – Picatinny – Package of two (2) bolts. Original factory replacement components for the entire line of TSR style of scope rings. SPECS: 4140 Alloy Steel, black oxide finish to Mil-C-13924 standards. .190″ (4.82mm) cross-slot wide. 1/4″ (6.35mm) diameter. Designed specifically for Mil-STD 1913 (Picatinny) mounts.