| INRIM | Istituto Nazionale di Ricerca Metrologica | Italy |
| Aalto | Aalto-korkeakoulusäätiö sr | Finland |
| CMI | Cesky Metrologicky Institut | Czech Republic |
| DFM | Dansk Fundamental Metrologi A/S | Denmark |
| METROSERT | AS Metrosert | Estonia |
| PTB | Physikalisch-Technische Bundesanstalt | Germany |
| HWU | Herriott-Watt University | United Kingdom |
| FCT-UNL | Faculdade de Ciências e Tecnologia Universidade Nova de Lisboa | Portugal |
| SQ | SPARROW QUANTUM | Denmark |
| Thales | Thales Sa | France |
| UNITO | Università degli Studi di Torino | Italy |
| ENS Paris-Saclay | Ecole Normale Supérieure Paris-Saclay | France |