This buckle is a replica of one found at the castrum of Vindonissa, in present-day Switzerland.
Measurements of buckle not including plate:
L=5.5 cm, W=6.2 cm, Plate width = 4 cm.
Ideal for a 4-5 cm strap.
Vindonissa was founded in AD 15 and converted into a civilian establishment in 101 AD. However, similar pieces have been found in Roman military settlements as far away as Britain such as these finds from the portable antiquities scheme.
https://finds.org.uk/database/artefacts/record/id/1031361
https://finds.org.uk/database/artefacts/record/id/951720
