| Model Num | Machine S/N Base |
|---|---|
| D6K2 | RPR |
| Category: Bulldog Hydraulic Kits -> Caterpillar -> Crawler Tractors | |
| D6K2 LGP | RST |
| Category: Bulldog Hydraulic Kits -> Caterpillar -> Crawler Tractors | |
| D6K2 XL | WMR |
| Category: Bulldog Hydraulic Kits -> Caterpillar -> Crawler Tractors | |
| D6K2 | MXK |
| Category: Bulldog Hydraulic Kits -> Caterpillar -> Crawler Tractors | |
| PL61 | WGS |
| Category: Bulldog Hydraulic Kits -> Caterpillar -> Pipelayers |