Divide into four stitch back muscle (take shape three muscle), three stitch back muscle (take shape two muscle), two stitch back muscle (take shape a muscle), Changing the difference of back muscle, only need to change different needle boards, press foot,
Divide into four stitch back muscle (take shape three muscle), three stitch back muscle (take shape two muscle), two stitch back muscle (take shape a muscle), Changing the difference of back muscle, only need to change different needle boards, press foot,
其中分为四针背筋（成形三根筋）、三针背筋（成形二根筋）、二针背筋（成形一根筋），转换背筋之分，只需更换不同的针板、压脚即可，操作很是方便。