4521 - 3-Ply adjustable collarete binder K710NA-A(S123A)-3/8" (28/10 mm) - suitable for Chain Stitch Machines like: Kansai Special DVK-1701F, DWK1802,… Pegasus W61, Rimoldi 261, Union Special 52800, 57700, Yamato DV-203, 1203, DW303, 1303,… With adjustable folding guides for smooth feeding. (equivalent: S123A3/8).