This 406 stitch is seen on the belt loop of a pant. It is a stitch formed by 2-needle threads passing through the material and inter looping with 1-looper thread with stitch set on the underside of the seam. Looper thread interlopers between needle threads providing seam coverage in the bottom side only. This seen on the left picture^ Needle And Thread, Seen, Wallet, Detail, Stitch, Pocket Wallet, Full Stop, Wallets, Stitches