Epson TM-C3500 Series Technical Reference Manual page 40

Wristband
<Back side>
Center of black marks
Center of paper width
Black mark width
Media type
Media source
Paper width
Black mark width
Black mark length
Center of a black mark
Gaps between black marks
Paper thickness
Paper core
External diameter
Winding direction
Hole, notch
40
<Printing side>
Center of paper width
WB-S/M/L series (Synthetic media)
Roll paper
WB-S/M/L series: 36 mm {1.42"}
13 mm {0.51"} or wider
5 mm {0.19"} or more
8.5 mm  1 mm {0.33  0.039"}
WB-S: 184.1 mm {7.25"}
WB-M: 292.1 mm {11.5"}
WB-L: 292.1 mm {11.5"}
WB-S/M/L series: 0.225 mm {0.0088"}
External diameter 56.8 mm or more
Maximum 101.6 mm {4"}
Printing face must be facing outside.
Diameter: 2.5 mm or less
Paper feeding
direction
Black mark paper