Authorized reproduction of the users / instruction manual for a Singer model 400w21, 400w22, 400w23. 400w24, 400w28, 400w29 and 400w33, a round bobbin sewing machine. It is described as a high speed, lock stitch sewing machine. This manual is NOT being reproduced from an original manual. The text is quite legible but the illustrations leave a bit to be desired. Our reproduction of this item is duplex laser printed in grayscale. The pages are coil bound so it will lay flat when opened and it has protective plastic covers.