FZ (R) N25-12 series indoor high-voltage vacuum load switch FZ (R) N21A-12 series h indoor high-voltage vacuum load switch FZ (R) N21-40.5 series indoor high-voltage vacuum load switch FZ (R) N16A-12 series indoor high-voltage vacuum load switch FKN12-12 (R) series pneumatic load switch FN7-12 series indoor high-voltage load switch FN5-12 series indoor high-voltage load switch FN3-12 series indoor high-voltage load switch