This is a set top high quality Double Toe Smooth bottom Welt Piping Foot 

for JUKI LS-1342 LS-1342-7 Cylinder-bed 1-Needle Union-feed  Industrial Walking Foot Machines.

There is an INSIDE Foot and an OUTSIDE 2 TOE Foot. Both feet have a GROOVE cut into their bottoms 

Piping size 3/16"(4.8mm)