| Company name | Reg. code |
|---|---|
| PROTOLANE OÜ kustutatud | 14468416 |
| PROTODYNE OÜ | 12600030 |
| PROTELINE OÜ | 17122434 |
| PROTOLAYER OÜ | 17464577 |
| PROMOLINE OÜ kustutatud | 10678849 |
| PROTOLAB OÜ | 10923065 |
| PROTOLA OÜ | 16420052 |
| PROTONE OÜ kustutatud | 11393652 |
| PROTOLA GROUP OÜ (former name Toppet OÜ) | 14894840 |
| PHOTOLINE OÜ | 11894124 |
| ROTOLARE OÜ (former name Küttevalvur OÜ) | 12439511 |
| MIMAKIKOKI GONDODELE OÜ (former name OÜ BIG SIX Holdings) | 14039922 |