size:6mm x 6mm

Hitachi models:
FD-10C, C-16, F-20, F-20A, HUS2, HUS3, HUS4, 
HUS5, HUS-ORN2, HUS-ORN3, HC-3, KS-4, HS-4, 
HUJ-RN, KBM-600, LDU2, LDU3, LDU4, LDU-4, 
LA12, NDU, PD-100, PDh-100, PDU-100, PDA-100
PDP-100, PDP-100B, PDB-100, PDH-100, PF-2
HUh-GN, HUN-GM2, LU-GN, LUV-GN, SN-10, TN-6, 
TN-6B, V-10, W6VE, W6VE, W6VF, W6VB