Following the Mayer Rod film coating principle, for higher viscosity fluids, the gap film coating rod reduces clogging and eliminates scratches. By winding smaller wires at pitches (see photo), the cavity created is wide and shallow, allowing thick coatings to flow better. Smaller wires create smaller interruptions in the coating flow, allowing for more complete wetting of the coating.

| Bar number | Steel Wire diameter (mm) | Coating thickness (μm) |
| RDS 80# | 2.032 | 182.88 |
| RDS 85 # | 2.159 | 194.31 |
| RDS 90 # | 2.286 | 205.74 |
| RDS 95 # | 2.413 | 217.17 |
| RDS 100 # | 2.54 | 228.6 |
| RDS 105 # | 2.667 | 240.03 |
| RDS 110 # | 2.794 | 251.46 |
| RDS 115 # | 2.921 | 262.89 |
| RDS 120 # | 3.048 | 274.32 |
| RDS 125 # | 3.175 | 285.75 |
| RDS 130 # | 3.302 | 297.18 |
| RDS 135 # | 3.429 | 308.61 |
| RDS 140 # | 3.556 | 320.04 |
| RDS 145 # | 3.683 | 331.47 |
| RDS 150 # | 3.81 | 342.9 |
| RDS 155 # | 3.937 | 354.33 |
| RDS 160 # | 4.064 | 365.76 |
| RDS 165 # | 4.191 | 377.19 |
| RDS 175 # | 4.445 | 400.05 |
| RDS 185 # | 4.699 | 422.91 |
| RDS 200 # | 5.08 | 457.2 |
| RDS 225 # | 5.715 | 514.35 |
| RDS 250 # | 6.35 | 571.5 |