1/4"-20 x 1-1/4" ASTM F879 Hex Drive 18-8 Stainless Steel Button Socket Cap Screw / THREAD CLASS: 3A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 1.21 INCHES MINIMUM AND 1.25 INCHES MAXIMUM FASTENER LENGTH: 1.21 INCHES MINIMUM AND 1.25 INCHES MAXIMUM HEAD STYLE: C30 BUTTON HEAD DIAMETER: 0.419 INCHES MINIMUM AND 0.437 INCHES MAXIMUM HEAD HEIGHT: 0.122 INCHES MINIMUM AND 0.132 INCHES MAXIMUM INTERNAL DRIVE STYLE: D5 HEXAGON END ITEM IDENTIFICATION: 2355-01-539-3639 NOMINAL THREAD DIAMETER: 0.25 INCHES WIDTH ACROSS FLATS: 0.1563 INCHES MINIMUM AND 0.1588 INCHES MAXIMUM THREAD QUANTITY PER INCH: 20 SPECIAL FEATURES: MATERIAL IS SS,ALLOY GROUP 1,ALLOY CONDITION CW PER ASTM F879 MATERIAL: STEEL CORROSION RESISTING OVERALL THREAD SERIES DESIGNATOR: UNC