BS BS 1127:1950 1127:1950

B B B B B B B

F140F150F170F180F190F300F310
1/8 – 1”3/16 – 1/21/8 – 2”1/8 – 1”No.7 – No.36M2 – M36M3 – M30
& 254& 255& 256& 257& 258& 259& 260
P1
P2
P3
P4
M1
M2
M3
M4
K1
K2
K3 K4
K5
N1
N2
N3
N4
N5
S1
S2 S3 S4
H1
H2
H3 H4