BSF, 5/8" x 2", Hex Head Bolt (partially threaded), High Tensile/ R/ 8.8, Self Colour, DIN 933.
BSF, 5/8" x 2" Hexagon Head Bolt (partially threaded with plain shank), High Tensile (R - 8.8), 4 pack.
R- Steel is an old term for 'Rail Steel' and is 8.8 high tensile steel in todays comparison
British Standard Fine (BSF)
A thread form based upon the British Standard Whitworth form but with a finer thread; more threads per inch and has the same thread angle as the BSW and smaller thread depth.
BSF was developed by R E B Crompton and his assistant George Field and was first introduced in 1908, the thread form is specified in BS 84: 1956
Standard, Free Delivery is Royal Mail, 2nd Class (2-5 days, most likely 2 days). For a faster delivery time, select 1st class or courier at checkout. Packs weighing under 250grams are upgraded to 1st class as much as possible,