本机型是综合送料厚料平缝机（双针）的版，采用大型立式旋梭（粗线旋梭）勾线，滑杆挑线。上下轴用滚针轴承支承，同步齿形带传动，柱塞式油泵润滑系统。采用针杆摆动兴压脚、送布牙同步送料方式。整机在综合性能上传动轻滑，噪声小，耐用度高，并设有保护旋梭超负荷的离合装置，确保了缝制品质量和旋梭的安全。本产品在4400基础上改进，加大操作空间（330mmx125mm)，针距达到12mm/针。特别适用于汽车座垫、安全带、安全气囊等汽车饰件的缝制，还可适用于手袋、箱包、账蓬、降落伞等大型器具的缝制。

This model is the latest product of compound feed lockstitcher (Double needle）, which is designed with large vertical rotating hook (Specially for thick thread) for thread loop catching and sliding bar for thread up-taking. The application of the needle bearings for arm shaft and hook shaft, cog belt driving, plunger oil pump for automatic lubrication. Compound feeding by needle bar, presser foot and feed dog provides this series with such splendid features as smooth running, quiet working and long service life. It is also equipped with a safety clutch to prevent the hook from damage by over-duty operation. This machine is derived from 4400, which increased the working space (520mm*150mm), it will sew 20 plies twisted thread at maximum, the stitch length gets to 12mm/needle. So it is especially availablein stitching car seats, safety belts,safety air bags, tents, parachutes, mat, sails, etc.