Replaces: BSR ST3 BSR ST4 ST6 ST-4 ST-5 ST-6 BSR ST-12 ST-14 ST15, Pfanstiehl 273-DS77. Used in: BSR C-1, SX1H, SX1M, X1H, X1M, X2HF, X3H, X4H, SX5H. Tip materials. 7 mil Diamond, Radii.7 mil Synthetic Sapphire.