OK, here goes,
421C landing gear, electrically controlled and hydraulically actuated. The individual landing gear actuators incorporate an internal lock to hold the landing gear in the extended position. The landing gear is held in the up position by mechanical uplocks which are released hydraulically during gear extension. Cycle completes in approximately 4.5 secs at max engine rpm. Pressure is supplied by hydraulic pumps mounted on each engine. The reservoir is located in the nose baggage compartment. There is a site gage for checking the level. The gear doors are mechanically linked to the gear. No inner doors.
Thats straight from the Cessna manual. If you need anything else, let me know.