Positive SSL
1 No.404半圓鍵,其鍵直徑及鍵寬分別為
A 1/2in,1/8in
B 1/2in,1/16in
C 1/8in,1/32in
D 1/4in,1/8in

D=4×1/8=1/2 in

b=4 ×1/32=1/8 in