Usually use hand wheel,impact hand wheel,worm gear box. Chain wheel and electric actuator can also be used if required by customer. Usually we use flexible graphite, also PTFE or other combined packing material can be used according to buyers. The internal surface of the stuffing box, of which area is contracted with the packing, is of excellent finish(3.2 aarh),can ensure the stem and packing combine close but rolled well. Back seat design: All our gate valves have back seat design. Normally, the carbon steel gate valve is fixed with a renewable backseat, for stainless steel gate valve, the backseat is machined directly in the bonnet or machined after welding. When the gate valve is at full open position,the sealing of the backseat can be reliable.However,as per API600,it’s not advisable to change packing when the valve is under pressure.